Update cafy to 8.0.0 :rocket:

94 files changed, 289 insertions, 286 deletions

diff --git a/src/server/api/endpoints/aggregation/posts.ts b/src/server/api/endpoints/aggregation/posts.ts
index 87e9af3a56..d348cadae9 100644
--- a/src/server/api/endpoints/aggregation/posts.ts
+++ b/src/server/api/endpoints/aggregation/posts.ts
@@ -9,7 +9,7 @@ import Note from '../../../../models/note';
  */
 module.exports = params => new Promise(async (res, rej) => {
 	// Get 'limit' parameter
-	const [limit = 365, limitErr] = $(params.limit).optional.number().range(1, 365).get();
+	const [limit = 365, limitErr] = $.num.optional().range(1, 365).get(params.limit);
 	if (limitErr) return rej('invalid limit param');
 
 	const datas = await Note
diff --git a/src/server/api/endpoints/aggregation/users.ts b/src/server/api/endpoints/aggregation/users.ts
index 831d771333..b116c1454b 100644
--- a/src/server/api/endpoints/aggregation/users.ts
+++ b/src/server/api/endpoints/aggregation/users.ts
@@ -9,7 +9,7 @@ import User from '../../../../models/user';
  */
 module.exports = params => new Promise(async (res, rej) => {
 	// Get 'limit' parameter
-	const [limit = 365, limitErr] = $(params.limit).optional.number().range(1, 365).get();
+	const [limit = 365, limitErr] = $.num.optional().range(1, 365).get(params.limit);
 	if (limitErr) return rej('invalid limit param');
 
 	const users = await User
diff --git a/src/server/api/endpoints/aggregation/users/activity.ts b/src/server/api/endpoints/aggregation/users/activity.ts
index 4a982ac3ba..9109487ac6 100644
--- a/src/server/api/endpoints/aggregation/users/activity.ts
+++ b/src/server/api/endpoints/aggregation/users/activity.ts
@@ -12,11 +12,11 @@ import Note from '../../../../../models/note';
  */
 module.exports = (params) => new Promise(async (res, rej) => {
 	// Get 'limit' parameter
-	const [limit = 365, limitErr] = $(params.limit).optional.number().range(1, 365).get();
+	const [limit = 365, limitErr] = $.num.optional().range(1, 365).get(params.limit);
 	if (limitErr) return rej('invalid limit param');
 
 	// Get 'userId' parameter
-	const [userId, userIdErr] = $(params.userId).type(ID).get();
+	const [userId, userIdErr] = $.type(ID).get(params.userId);
 	if (userIdErr) return rej('invalid userId param');
 
 	// Lookup user
diff --git a/src/server/api/endpoints/aggregation/users/followers.ts b/src/server/api/endpoints/aggregation/users/followers.ts
index 3079542c67..dfcaf8462f 100644
--- a/src/server/api/endpoints/aggregation/users/followers.ts
+++ b/src/server/api/endpoints/aggregation/users/followers.ts
@@ -10,7 +10,7 @@ import FollowedLog from '../../../../../models/followed-log';
  */
 module.exports = (params) => new Promise(async (res, rej) => {
 	// Get 'userId' parameter
-	const [userId, userIdErr] = $(params.userId).type(ID).get();
+	const [userId, userIdErr] = $.type(ID).get(params.userId);
 	if (userIdErr) return rej('invalid userId param');
 
 	// Lookup user
diff --git a/src/server/api/endpoints/aggregation/users/following.ts b/src/server/api/endpoints/aggregation/users/following.ts
index 4efe20230d..5f826fd71c 100644
--- a/src/server/api/endpoints/aggregation/users/following.ts
+++ b/src/server/api/endpoints/aggregation/users/following.ts
@@ -10,7 +10,7 @@ import FollowingLog from '../../../../../models/following-log';
  */
 module.exports = (params) => new Promise(async (res, rej) => {
 	// Get 'userId' parameter
-	const [userId, userIdErr] = $(params.userId).type(ID).get();
+	const [userId, userIdErr] = $.type(ID).get(params.userId);
 	if (userIdErr) return rej('invalid userId param');
 
 	// Lookup user
diff --git a/src/server/api/endpoints/aggregation/users/post.ts b/src/server/api/endpoints/aggregation/users/post.ts
index fc6541065b..11f9ef14cd 100644
--- a/src/server/api/endpoints/aggregation/users/post.ts
+++ b/src/server/api/endpoints/aggregation/users/post.ts
@@ -10,7 +10,7 @@ import Note from '../../../../../models/note';
  */
 module.exports = (params) => new Promise(async (res, rej) => {
 	// Get 'userId' parameter
-	const [userId, userIdErr] = $(params.userId).type(ID).get();
+	const [userId, userIdErr] = $.type(ID).get(params.userId);
 	if (userIdErr) return rej('invalid userId param');
 
 	// Lookup user
diff --git a/src/server/api/endpoints/aggregation/users/reaction.ts b/src/server/api/endpoints/aggregation/users/reaction.ts
index ea3363e1aa..2de2840258 100644
--- a/src/server/api/endpoints/aggregation/users/reaction.ts
+++ b/src/server/api/endpoints/aggregation/users/reaction.ts
@@ -13,7 +13,7 @@ import Reaction from '../../../../../models/note-reaction';
  */
 module.exports = (params) => new Promise(async (res, rej) => {
 	// Get 'userId' parameter
-	const [userId, userIdErr] = $(params.userId).type(ID).get();
+	const [userId, userIdErr] = $.type(ID).get(params.userId);
 	if (userIdErr) return rej('invalid userId param');
 
 	// Lookup user
diff --git a/src/server/api/endpoints/app/create.ts b/src/server/api/endpoints/app/create.ts
index 97154690fa..553bd2381a 100644
--- a/src/server/api/endpoints/app/create.ts
+++ b/src/server/api/endpoints/app/create.ts
@@ -67,24 +67,24 @@ import App, { isValidNameId, pack } from '../../../../models/app';
  */
 module.exports = async (params, user) => new Promise(async (res, rej) => {
 	// Get 'nameId' parameter
-	const [nameId, nameIdErr] = $(params.nameId).string().pipe(isValidNameId).get();
+	const [nameId, nameIdErr] = $.str.pipe(isValidNameId).get(params.nameId);
 	if (nameIdErr) return rej('invalid nameId param');
 
 	// Get 'name' parameter
-	const [name, nameErr] = $(params.name).string().get();
+	const [name, nameErr] = $.str.get(params.name);
 	if (nameErr) return rej('invalid name param');
 
 	// Get 'description' parameter
-	const [description, descriptionErr] = $(params.description).string().get();
+	const [description, descriptionErr] = $.str.get(params.description);
 	if (descriptionErr) return rej('invalid description param');
 
 	// Get 'permission' parameter
-	const [permission, permissionErr] = $(params.permission).array($().string()).unique().get();
+	const [permission, permissionErr] = $.arr($.str).unique().get(params.permission);
 	if (permissionErr) return rej('invalid permission param');
 
 	// Get 'callbackUrl' parameter
 	// TODO: Check it is valid url
-	const [callbackUrl = null, callbackUrlErr] = $(params.callbackUrl).optional.nullable.string().get();
+	const [callbackUrl = null, callbackUrlErr] = $.str.optional().nullable().get(params.callbackUrl);
 	if (callbackUrlErr) return rej('invalid callbackUrl param');
 
 	// Generate secret
diff --git a/src/server/api/endpoints/app/name_id/available.ts b/src/server/api/endpoints/app/name_id/available.ts
index 8c32a780ec..135bb7d2b4 100644
--- a/src/server/api/endpoints/app/name_id/available.ts
+++ b/src/server/api/endpoints/app/name_id/available.ts
@@ -42,7 +42,7 @@ import { isValidNameId } from '../../../../../models/app';
  */
 module.exports = async (params) => new Promise(async (res, rej) => {
 	// Get 'nameId' parameter
-	const [nameId, nameIdErr] = $(params.nameId).string().pipe(isValidNameId).get();
+	const [nameId, nameIdErr] = $.str.pipe(isValidNameId).get(params.nameId);
 	if (nameIdErr) return rej('invalid nameId param');
 
 	// Get exist
diff --git a/src/server/api/endpoints/app/show.ts b/src/server/api/endpoints/app/show.ts
index 8408850285..8d742ab182 100644
--- a/src/server/api/endpoints/app/show.ts
+++ b/src/server/api/endpoints/app/show.ts
@@ -41,11 +41,11 @@ module.exports = (params, user, app) => new Promise(async (res, rej) => {
 	const isSecure = user != null && app == null;
 
 	// Get 'appId' parameter
-	const [appId, appIdErr] = $(params.appId).optional.type(ID).get();
+	const [appId, appIdErr] = $.type(ID).optional().get(params.appId);
 	if (appIdErr) return rej('invalid appId param');
 
 	// Get 'nameId' parameter
-	const [nameId, nameIdErr] = $(params.nameId).optional.string().get();
+	const [nameId, nameIdErr] = $.str.optional().get(params.nameId);
 	if (nameIdErr) return rej('invalid nameId param');
 
 	if (appId === undefined && nameId === undefined) {
diff --git a/src/server/api/endpoints/auth/accept.ts b/src/server/api/endpoints/auth/accept.ts
index cb271f9d67..695fbb0803 100644
--- a/src/server/api/endpoints/auth/accept.ts
+++ b/src/server/api/endpoints/auth/accept.ts
@@ -40,7 +40,7 @@ import AccessToken from '../../../../models/access-token';
  */
 module.exports = (params, user) => new Promise(async (res, rej) => {
 	// Get 'token' parameter
-	const [token, tokenErr] = $(params.token).string().get();
+	const [token, tokenErr] = $.str.get(params.token);
 	if (tokenErr) return rej('invalid token param');
 
 	// Fetch token
diff --git a/src/server/api/endpoints/auth/session/generate.ts b/src/server/api/endpoints/auth/session/generate.ts
index 8d243b85cf..d649a8d902 100644
--- a/src/server/api/endpoints/auth/session/generate.ts
+++ b/src/server/api/endpoints/auth/session/generate.ts
@@ -46,7 +46,7 @@ import config from '../../../../../config';
  */
 module.exports = (params) => new Promise(async (res, rej) => {
 	// Get 'appSecret' parameter
-	const [appSecret, appSecretErr] = $(params.appSecret).string().get();
+	const [appSecret, appSecretErr] = $.str.get(params.appSecret);
 	if (appSecretErr) return rej('invalid appSecret param');
 
 	// Lookup app
diff --git a/src/server/api/endpoints/auth/session/show.ts b/src/server/api/endpoints/auth/session/show.ts
index 87a43c94b9..434cc264a0 100644
--- a/src/server/api/endpoints/auth/session/show.ts
+++ b/src/server/api/endpoints/auth/session/show.ts
@@ -53,7 +53,7 @@ import AuthSess, { pack } from '../../../../../models/auth-session';
  */
 module.exports = (params, user) => new Promise(async (res, rej) => {
 	// Get 'token' parameter
-	const [token, tokenErr] = $(params.token).string().get();
+	const [token, tokenErr] = $.str.get(params.token);
 	if (tokenErr) return rej('invalid token param');
 
 	// Lookup session
diff --git a/src/server/api/endpoints/auth/session/userkey.ts b/src/server/api/endpoints/auth/session/userkey.ts
index 29642e6327..3026b477f1 100644
--- a/src/server/api/endpoints/auth/session/userkey.ts
+++ b/src/server/api/endpoints/auth/session/userkey.ts
@@ -51,7 +51,7 @@ import { pack } from '../../../../../models/user';
  */
 module.exports = (params) => new Promise(async (res, rej) => {
 	// Get 'appSecret' parameter
-	const [appSecret, appSecretErr] = $(params.appSecret).string().get();
+	const [appSecret, appSecretErr] = $.str.get(params.appSecret);
 	if (appSecretErr) return rej('invalid appSecret param');
 
 	// Lookup app
@@ -64,7 +64,7 @@ module.exports = (params) => new Promise(async (res, rej) => {
 	}
 
 	// Get 'token' parameter
-	const [token, tokenErr] = $(params.token).string().get();
+	const [token, tokenErr] = $.str.get(params.token);
 	if (tokenErr) return rej('invalid token param');
 
 	// Fetch token
diff --git a/src/server/api/endpoints/channels.ts b/src/server/api/endpoints/channels.ts
index 9fd0fcb89c..ceef4b9cb9 100644
--- a/src/server/api/endpoints/channels.ts
+++ b/src/server/api/endpoints/channels.ts
@@ -13,15 +13,15 @@ import Channel, { pack } from '../../../models/channel';
  */
 module.exports = (params, me) => new Promise(async (res, rej) => {
 	// Get 'limit' parameter
-	const [limit = 10, limitErr] = $(params.limit).optional.number().range(1, 100).get();
+	const [limit = 10, limitErr] = $.num.optional().range(1, 100).get(params.limit);
 	if (limitErr) return rej('invalid limit param');
 
 	// Get 'sinceId' parameter
-	const [sinceId, sinceIdErr] = $(params.sinceId).optional.type(ID).get();
+	const [sinceId, sinceIdErr] = $.type(ID).optional().get(params.sinceId);
 	if (sinceIdErr) return rej('invalid sinceId param');
 
 	// Get 'untilId' parameter
-	const [untilId, untilIdErr] = $(params.untilId).optional.type(ID).get();
+	const [untilId, untilIdErr] = $.type(ID).optional().get(params.untilId);
 	if (untilIdErr) return rej('invalid untilId param');
 
 	// Check if both of sinceId and untilId is specified
diff --git a/src/server/api/endpoints/channels/create.ts b/src/server/api/endpoints/channels/create.ts
index 2574e0923d..0e3c9dc5ac 100644
--- a/src/server/api/endpoints/channels/create.ts
+++ b/src/server/api/endpoints/channels/create.ts
@@ -11,7 +11,7 @@ import { pack } from '../../../../models/channel';
  */
 module.exports = async (params, user) => new Promise(async (res, rej) => {
 	// Get 'title' parameter
-	const [title, titleErr] = $(params.title).string().range(1, 100).get();
+	const [title, titleErr] = $.str.range(1, 100).get(params.title);
 	if (titleErr) return rej('invalid title param');
 
 	// Create a channel
diff --git a/src/server/api/endpoints/channels/notes.ts b/src/server/api/endpoints/channels/notes.ts
index a83cdb34c4..463152e74a 100644
--- a/src/server/api/endpoints/channels/notes.ts
+++ b/src/server/api/endpoints/channels/notes.ts
@@ -10,15 +10,15 @@ import Note, { pack } from '../../../../models/note';
  */
 module.exports = (params, user) => new Promise(async (res, rej) => {
 	// Get 'limit' parameter
-	const [limit = 1000, limitErr] = $(params.limit).optional.number().range(1, 1000).get();
+	const [limit = 1000, limitErr] = $.num.optional().range(1, 1000).get(params.limit);
 	if (limitErr) return rej('invalid limit param');
 
 	// Get 'sinceId' parameter
-	const [sinceId, sinceIdErr] = $(params.sinceId).optional.type(ID).get();
+	const [sinceId, sinceIdErr] = $.type(ID).optional().get(params.sinceId);
 	if (sinceIdErr) return rej('invalid sinceId param');
 
 	// Get 'untilId' parameter
-	const [untilId, untilIdErr] = $(params.untilId).optional.type(ID).get();
+	const [untilId, untilIdErr] = $.type(ID).optional().get(params.untilId);
 	if (untilIdErr) return rej('invalid untilId param');
 
 	// Check if both of sinceId and untilId is specified
@@ -27,7 +27,7 @@ module.exports = (params, user) => new Promise(async (res, rej) => {
 	}
 
 	// Get 'channelId' parameter
-	const [channelId, channelIdErr] = $(params.channelId).type(ID).get();
+	const [channelId, channelIdErr] = $.type(ID).get(params.channelId);
 	if (channelIdErr) return rej('invalid channelId param');
 
 	// Fetch channel
diff --git a/src/server/api/endpoints/channels/show.ts b/src/server/api/endpoints/channels/show.ts
index d5ca4ba3b7..1bba63d490 100644
--- a/src/server/api/endpoints/channels/show.ts
+++ b/src/server/api/endpoints/channels/show.ts
@@ -9,7 +9,7 @@ import Channel, { IChannel, pack } from '../../../../models/channel';
  */
 module.exports = (params, user) => new Promise(async (res, rej) => {
 	// Get 'channelId' parameter
-	const [channelId, channelIdErr] = $(params.channelId).type(ID).get();
+	const [channelId, channelIdErr] = $.type(ID).get(params.channelId);
 	if (channelIdErr) return rej('invalid channelId param');
 
 	// Fetch channel
diff --git a/src/server/api/endpoints/channels/unwatch.ts b/src/server/api/endpoints/channels/unwatch.ts
index 9385e209df..f7dddff461 100644
--- a/src/server/api/endpoints/channels/unwatch.ts
+++ b/src/server/api/endpoints/channels/unwatch.ts
@@ -10,7 +10,7 @@ import Watching from '../../../../models/channel-watching';
  */
 module.exports = (params, user) => new Promise(async (res, rej) => {
 	// Get 'channelId' parameter
-	const [channelId, channelIdErr] = $(params.channelId).type(ID).get();
+	const [channelId, channelIdErr] = $.type(ID).get(params.channelId);
 	if (channelIdErr) return rej('invalid channelId param');
 
 	//#region Fetch channel
diff --git a/src/server/api/endpoints/channels/watch.ts b/src/server/api/endpoints/channels/watch.ts
index ceda3b130a..34243ff68b 100644
--- a/src/server/api/endpoints/channels/watch.ts
+++ b/src/server/api/endpoints/channels/watch.ts
@@ -10,7 +10,7 @@ import Watching from '../../../../models/channel-watching';
  */
 module.exports = (params, user) => new Promise(async (res, rej) => {
 	// Get 'channelId' parameter
-	const [channelId, channelIdErr] = $(params.channelId).type(ID).get();
+	const [channelId, channelIdErr] = $.type(ID).get(params.channelId);
 	if (channelIdErr) return rej('invalid channelId param');
 
 	//#region Fetch channel
diff --git a/src/server/api/endpoints/drive/files.ts b/src/server/api/endpoints/drive/files.ts
index 52dfe60faf..ab4b18cef4 100644
--- a/src/server/api/endpoints/drive/files.ts
+++ b/src/server/api/endpoints/drive/files.ts
@@ -9,15 +9,15 @@ import DriveFile, { pack } from '../../../../models/drive-file';
  */
 module.exports = async (params, user, app) => {
 	// Get 'limit' parameter
-	const [limit = 10, limitErr] = $(params.limit).optional.number().range(1, 100).get();
+	const [limit = 10, limitErr] = $.num.optional().range(1, 100).get(params.limit);
 	if (limitErr) throw 'invalid limit param';
 
 	// Get 'sinceId' parameter
-	const [sinceId, sinceIdErr] = $(params.sinceId).optional.type(ID).get();
+	const [sinceId, sinceIdErr] = $.type(ID).optional().get(params.sinceId);
 	if (sinceIdErr) throw 'invalid sinceId param';
 
 	// Get 'untilId' parameter
-	const [untilId, untilIdErr] = $(params.untilId).optional.type(ID).get();
+	const [untilId, untilIdErr] = $.type(ID).optional().get(params.untilId);
 	if (untilIdErr) throw 'invalid untilId param';
 
 	// Check if both of sinceId and untilId is specified
@@ -26,11 +26,11 @@ module.exports = async (params, user, app) => {
 	}
 
 	// Get 'folderId' parameter
-	const [folderId = null, folderIdErr] = $(params.folderId).optional.nullable.type(ID).get();
+	const [folderId = null, folderIdErr] = $.type(ID).optional().nullable().get(params.folderId);
 	if (folderIdErr) throw 'invalid folderId param';
 
 	// Get 'type' parameter
-	const [type, typeErr] = $(params.type).optional.string().match(/^[a-zA-Z\/\-\*]+$/).get();
+	const [type, typeErr] = $.str.optional().match(/^[a-zA-Z\/\-\*]+$/).get(params.type);
 	if (typeErr) throw 'invalid type param';
 
 	// Construct query
diff --git a/src/server/api/endpoints/drive/files/create.ts b/src/server/api/endpoints/drive/files/create.ts
index b1a4bc9c52..e9348e4e2f 100644
--- a/src/server/api/endpoints/drive/files/create.ts
+++ b/src/server/api/endpoints/drive/files/create.ts
@@ -29,7 +29,7 @@ module.exports = async (file, params, user): Promise<any> => {
 	}
 
 	// Get 'folderId' parameter
-	const [folderId = null, folderIdErr] = $(params.folderId).optional.nullable.type(ID).get();
+	const [folderId = null, folderIdErr] = $.type(ID).optional().nullable().get(params.folderId);
 	if (folderIdErr) throw 'invalid folderId param';
 
 	try {
diff --git a/src/server/api/endpoints/drive/files/find.ts b/src/server/api/endpoints/drive/files/find.ts
index 4636d85050..98165990fe 100644
--- a/src/server/api/endpoints/drive/files/find.ts
+++ b/src/server/api/endpoints/drive/files/find.ts
@@ -9,11 +9,11 @@ import DriveFile, { pack } from '../../../../../models/drive-file';
  */
 module.exports = (params, user) => new Promise(async (res, rej) => {
 	// Get 'name' parameter
-	const [name, nameErr] = $(params.name).string().get();
+	const [name, nameErr] = $.str.get(params.name);
 	if (nameErr) return rej('invalid name param');
 
 	// Get 'folderId' parameter
-	const [folderId = null, folderIdErr] = $(params.folderId).optional.nullable.type(ID).get();
+	const [folderId = null, folderIdErr] = $.type(ID).optional().nullable().get(params.folderId);
 	if (folderIdErr) return rej('invalid folderId param');
 
 	// Issue query
diff --git a/src/server/api/endpoints/drive/files/show.ts b/src/server/api/endpoints/drive/files/show.ts
index 7e62e12fad..c7efda7ab0 100644
--- a/src/server/api/endpoints/drive/files/show.ts
+++ b/src/server/api/endpoints/drive/files/show.ts
@@ -9,7 +9,7 @@ import DriveFile, { pack } from '../../../../../models/drive-file';
  */
 module.exports = async (params, user) => {
 	// Get 'fileId' parameter
-	const [fileId, fileIdErr] = $(params.fileId).type(ID).get();
+	const [fileId, fileIdErr] = $.type(ID).get(params.fileId);
 	if (fileIdErr) throw 'invalid fileId param';
 
 	// Fetch file
diff --git a/src/server/api/endpoints/drive/files/update.ts b/src/server/api/endpoints/drive/files/update.ts
index c80e26771c..12fa8e025d 100644
--- a/src/server/api/endpoints/drive/files/update.ts
+++ b/src/server/api/endpoints/drive/files/update.ts
@@ -11,7 +11,7 @@ import { publishDriveStream } from '../../../../../publishers/stream';
  */
 module.exports = (params, user) => new Promise(async (res, rej) => {
 	// Get 'fileId' parameter
-	const [fileId, fileIdErr] = $(params.fileId).type(ID).get();
+	const [fileId, fileIdErr] = $.type(ID).get(params.fileId);
 	if (fileIdErr) return rej('invalid fileId param');
 
 	// Fetch file
@@ -26,12 +26,12 @@ module.exports = (params, user) => new Promise(async (res, rej) => {
 	}
 
 	// Get 'name' parameter
-	const [name, nameErr] = $(params.name).optional.string().pipe(validateFileName).get();
+	const [name, nameErr] = $.str.optional().pipe(validateFileName).get(params.name);
 	if (nameErr) return rej('invalid name param');
 	if (name) file.filename = name;
 
 	// Get 'folderId' parameter
-	const [folderId, folderIdErr] = $(params.folderId).optional.nullable.type(ID).get();
+	const [folderId, folderIdErr] = $.type(ID).optional().nullable().get(params.folderId);
 	if (folderIdErr) return rej('invalid folderId param');
 
 	if (folderId !== undefined) {
diff --git a/src/server/api/endpoints/drive/files/upload_from_url.ts b/src/server/api/endpoints/drive/files/upload_from_url.ts
index 540c317bee..c012f0d3c9 100644
--- a/src/server/api/endpoints/drive/files/upload_from_url.ts
+++ b/src/server/api/endpoints/drive/files/upload_from_url.ts
@@ -11,11 +11,11 @@ import uploadFromUrl from '../../../../../services/drive/upload-from-url';
 module.exports = async (params, user): Promise<any> => {
 	// Get 'url' parameter
 	// TODO: Validate this url
-	const [url, urlErr] = $(params.url).string().get();
+	const [url, urlErr] = $.str.get(params.url);
 	if (urlErr) throw 'invalid url param';
 
 	// Get 'folderId' parameter
-	const [folderId = null, folderIdErr] = $(params.folderId).optional.nullable.type(ID).get();
+	const [folderId = null, folderIdErr] = $.type(ID).optional().nullable().get(params.folderId);
 	if (folderIdErr) throw 'invalid folderId param';
 
 	return pack(await uploadFromUrl(url, user, folderId));
diff --git a/src/server/api/endpoints/drive/folders.ts b/src/server/api/endpoints/drive/folders.ts
index 8193a8317a..bc6c50eb99 100644
--- a/src/server/api/endpoints/drive/folders.ts
+++ b/src/server/api/endpoints/drive/folders.ts
@@ -9,15 +9,15 @@ import DriveFolder, { pack } from '../../../../models/drive-folder';
  */
 module.exports = (params, user, app) => new Promise(async (res, rej) => {
 	// Get 'limit' parameter
-	const [limit = 10, limitErr] = $(params.limit).optional.number().range(1, 100).get();
+	const [limit = 10, limitErr] = $.num.optional().range(1, 100).get(params.limit);
 	if (limitErr) return rej('invalid limit param');
 
 	// Get 'sinceId' parameter
-	const [sinceId, sinceIdErr] = $(params.sinceId).optional.type(ID).get();
+	const [sinceId, sinceIdErr] = $.type(ID).optional().get(params.sinceId);
 	if (sinceIdErr) return rej('invalid sinceId param');
 
 	// Get 'untilId' parameter
-	const [untilId, untilIdErr] = $(params.untilId).optional.type(ID).get();
+	const [untilId, untilIdErr] = $.type(ID).optional().get(params.untilId);
 	if (untilIdErr) return rej('invalid untilId param');
 
 	// Check if both of sinceId and untilId is specified
@@ -26,7 +26,7 @@ module.exports = (params, user, app) => new Promise(async (res, rej) => {
 	}
 
 	// Get 'folderId' parameter
-	const [folderId = null, folderIdErr] = $(params.folderId).optional.nullable.type(ID).get();
+	const [folderId = null, folderIdErr] = $.type(ID).optional().nullable().get(params.folderId);
 	if (folderIdErr) return rej('invalid folderId param');
 
 	// Construct query
diff --git a/src/server/api/endpoints/drive/folders/create.ts b/src/server/api/endpoints/drive/folders/create.ts
index 487c1b2205..62e3b6f6e8 100644
--- a/src/server/api/endpoints/drive/folders/create.ts
+++ b/src/server/api/endpoints/drive/folders/create.ts
@@ -10,11 +10,11 @@ import { publishDriveStream } from '../../../../../publishers/stream';
  */
 module.exports = (params, user) => new Promise(async (res, rej) => {
 	// Get 'name' parameter
-	const [name = '無題のフォルダー', nameErr] = $(params.name).optional.string().pipe(isValidFolderName).get();
+	const [name = '無題のフォルダー', nameErr] = $.str.optional().pipe(isValidFolderName).get(params.name);
 	if (nameErr) return rej('invalid name param');
 
 	// Get 'parentId' parameter
-	const [parentId = null, parentIdErr] = $(params.parentId).optional.nullable.type(ID).get();
+	const [parentId = null, parentIdErr] = $.type(ID).optional().nullable().get(params.parentId);
 	if (parentIdErr) return rej('invalid parentId param');
 
 	// If the parent folder is specified
diff --git a/src/server/api/endpoints/drive/folders/find.ts b/src/server/api/endpoints/drive/folders/find.ts
index b8579219f9..9703d9e99d 100644
--- a/src/server/api/endpoints/drive/folders/find.ts
+++ b/src/server/api/endpoints/drive/folders/find.ts
@@ -9,11 +9,11 @@ import DriveFolder, { pack } from '../../../../../models/drive-folder';
  */
 module.exports = (params, user) => new Promise(async (res, rej) => {
 	// Get 'name' parameter
-	const [name, nameErr] = $(params.name).string().get();
+	const [name, nameErr] = $.str.get(params.name);
 	if (nameErr) return rej('invalid name param');
 
 	// Get 'parentId' parameter
-	const [parentId = null, parentIdErr] = $(params.parentId).optional.nullable.type(ID).get();
+	const [parentId = null, parentIdErr] = $.type(ID).optional().nullable().get(params.parentId);
 	if (parentIdErr) return rej('invalid parentId param');
 
 	// Issue query
diff --git a/src/server/api/endpoints/drive/folders/show.ts b/src/server/api/endpoints/drive/folders/show.ts
index 36d7f1c69f..44f1889001 100644
--- a/src/server/api/endpoints/drive/folders/show.ts
+++ b/src/server/api/endpoints/drive/folders/show.ts
@@ -9,7 +9,7 @@ import DriveFolder, { pack } from '../../../../../models/drive-folder';
  */
 module.exports = (params, user) => new Promise(async (res, rej) => {
 	// Get 'folderId' parameter
-	const [folderId, folderIdErr] = $(params.folderId).type(ID).get();
+	const [folderId, folderIdErr] = $.type(ID).get(params.folderId);
 	if (folderIdErr) return rej('invalid folderId param');
 
 	// Get folder
diff --git a/src/server/api/endpoints/drive/folders/update.ts b/src/server/api/endpoints/drive/folders/update.ts
index 64a6cd293a..e24d8a14cd 100644
--- a/src/server/api/endpoints/drive/folders/update.ts
+++ b/src/server/api/endpoints/drive/folders/update.ts
@@ -10,7 +10,7 @@ import { publishDriveStream } from '../../../../../publishers/stream';
  */
 module.exports = (params, user) => new Promise(async (res, rej) => {
 	// Get 'folderId' parameter
-	const [folderId, folderIdErr] = $(params.folderId).type(ID).get();
+	const [folderId, folderIdErr] = $.type(ID).get(params.folderId);
 	if (folderIdErr) return rej('invalid folderId param');
 
 	// Fetch folder
@@ -25,12 +25,12 @@ module.exports = (params, user) => new Promise(async (res, rej) => {
 	}
 
 	// Get 'name' parameter
-	const [name, nameErr] = $(params.name).optional.string().pipe(isValidFolderName).get();
+	const [name, nameErr] = $.str.optional().pipe(isValidFolderName).get(params.name);
 	if (nameErr) return rej('invalid name param');
 	if (name) folder.name = name;
 
 	// Get 'parentId' parameter
-	const [parentId, parentIdErr] = $(params.parentId).optional.nullable.type(ID).get();
+	const [parentId, parentIdErr] = $.type(ID).optional().nullable().get(params.parentId);
 	if (parentIdErr) return rej('invalid parentId param');
 	if (parentId !== undefined) {
 		if (parentId === null) {
diff --git a/src/server/api/endpoints/drive/stream.ts b/src/server/api/endpoints/drive/stream.ts
index b148f2ce51..8cb3a99b42 100644
--- a/src/server/api/endpoints/drive/stream.ts
+++ b/src/server/api/endpoints/drive/stream.ts
@@ -9,15 +9,15 @@ import DriveFile, { pack } from '../../../../models/drive-file';
  */
 module.exports = (params, user) => new Promise(async (res, rej) => {
 	// Get 'limit' parameter
-	const [limit = 10, limitErr] = $(params.limit).optional.number().range(1, 100).get();
+	const [limit = 10, limitErr] = $.num.optional().range(1, 100).get(params.limit);
 	if (limitErr) return rej('invalid limit param');
 
 	// Get 'sinceId' parameter
-	const [sinceId, sinceIdErr] = $(params.sinceId).optional.type(ID).get();
+	const [sinceId, sinceIdErr] = $.type(ID).optional().get(params.sinceId);
 	if (sinceIdErr) return rej('invalid sinceId param');
 
 	// Get 'untilId' parameter
-	const [untilId, untilIdErr] = $(params.untilId).optional.type(ID).get();
+	const [untilId, untilIdErr] = $.type(ID).optional().get(params.untilId);
 	if (untilIdErr) return rej('invalid untilId param');
 
 	// Check if both of sinceId and untilId is specified
@@ -26,7 +26,7 @@ module.exports = (params, user) => new Promise(async (res, rej) => {
 	}
 
 	// Get 'type' parameter
-	const [type, typeErr] = $(params.type).optional.string().match(/^[a-zA-Z\/\-\*]+$/).get();
+	const [type, typeErr] = $.str.optional().match(/^[a-zA-Z\/\-\*]+$/).get(params.type);
 	if (typeErr) return rej('invalid type param');
 
 	// Construct query
diff --git a/src/server/api/endpoints/following/create.ts b/src/server/api/endpoints/following/create.ts
index 42a7b79b00..766a8c03d0 100644
--- a/src/server/api/endpoints/following/create.ts
+++ b/src/server/api/endpoints/following/create.ts
@@ -13,7 +13,7 @@ module.exports = (params, user) => new Promise(async (res, rej) => {
 	const follower = user;
 
 	// Get 'userId' parameter
-	const [userId, userIdErr] = $(params.userId).type(ID).get();
+	const [userId, userIdErr] = $.type(ID).get(params.userId);
 	if (userIdErr) return rej('invalid userId param');
 
 	// 自分自身
diff --git a/src/server/api/endpoints/following/delete.ts b/src/server/api/endpoints/following/delete.ts
index 3aef6523de..396b19a6f6 100644
--- a/src/server/api/endpoints/following/delete.ts
+++ b/src/server/api/endpoints/following/delete.ts
@@ -13,7 +13,7 @@ module.exports = (params, user) => new Promise(async (res, rej) => {
 	const follower = user;
 
 	// Get 'userId' parameter
-	const [userId, userIdErr] = $(params.userId).type(ID).get();
+	const [userId, userIdErr] = $.type(ID).get(params.userId);
 	if (userIdErr) return rej('invalid userId param');
 
 	// Check if the followee is yourself
diff --git a/src/server/api/endpoints/following/stalk.ts b/src/server/api/endpoints/following/stalk.ts
index 34e3f80f8a..f0bc8cbdfc 100644
--- a/src/server/api/endpoints/following/stalk.ts
+++ b/src/server/api/endpoints/following/stalk.ts
@@ -8,7 +8,7 @@ module.exports = (params, user) => new Promise(async (res, rej) => {
 	const follower = user;
 
 	// Get 'userId' parameter
-	const [userId, userIdErr] = $(params.userId).type(ID).get();
+	const [userId, userIdErr] = $.type(ID).get(params.userId);
 	if (userIdErr) return rej('invalid userId param');
 
 	// Fetch following
diff --git a/src/server/api/endpoints/following/unstalk.ts b/src/server/api/endpoints/following/unstalk.ts
index f8ca39ef7d..0d0a018c34 100644
--- a/src/server/api/endpoints/following/unstalk.ts
+++ b/src/server/api/endpoints/following/unstalk.ts
@@ -8,7 +8,7 @@ module.exports = (params, user) => new Promise(async (res, rej) => {
 	const follower = user;
 
 	// Get 'userId' parameter
-	const [userId, userIdErr] = $(params.userId).type(ID).get();
+	const [userId, userIdErr] = $.type(ID).get(params.userId);
 	if (userIdErr) return rej('invalid userId param');
 
 	// Fetch following
diff --git a/src/server/api/endpoints/i/2fa/done.ts b/src/server/api/endpoints/i/2fa/done.ts
index 310e5c574e..1a2706aa84 100644
--- a/src/server/api/endpoints/i/2fa/done.ts
+++ b/src/server/api/endpoints/i/2fa/done.ts
@@ -7,7 +7,7 @@ import User from '../../../../../models/user';
 
 module.exports = async (params, user) => new Promise(async (res, rej) => {
 	// Get 'token' parameter
-	const [token, tokenErr] = $(params.token).string().get();
+	const [token, tokenErr] = $.str.get(params.token);
 	if (tokenErr) return rej('invalid token param');
 
 	const _token = token.replace(/\s/g, '');
diff --git a/src/server/api/endpoints/i/2fa/register.ts b/src/server/api/endpoints/i/2fa/register.ts
index 51f66dc2fe..d314e1a280 100644
--- a/src/server/api/endpoints/i/2fa/register.ts
+++ b/src/server/api/endpoints/i/2fa/register.ts
@@ -10,7 +10,7 @@ import config from '../../../../../config';
 
 module.exports = async (params, user) => new Promise(async (res, rej) => {
 	// Get 'password' parameter
-	const [password, passwordErr] = $(params.password).string().get();
+	const [password, passwordErr] = $.str.get(params.password);
 	if (passwordErr) return rej('invalid password param');
 
 	// Compare password
diff --git a/src/server/api/endpoints/i/2fa/unregister.ts b/src/server/api/endpoints/i/2fa/unregister.ts
index 9fd940dcaf..336a3564ab 100644
--- a/src/server/api/endpoints/i/2fa/unregister.ts
+++ b/src/server/api/endpoints/i/2fa/unregister.ts
@@ -7,7 +7,7 @@ import User from '../../../../../models/user';
 
 module.exports = async (params, user) => new Promise(async (res, rej) => {
 	// Get 'password' parameter
-	const [password, passwordErr] = $(params.password).string().get();
+	const [password, passwordErr] = $.str.get(params.password);
 	if (passwordErr) return rej('invalid password param');
 
 	// Compare password
diff --git a/src/server/api/endpoints/i/authorized_apps.ts b/src/server/api/endpoints/i/authorized_apps.ts
index 9635091465..d15bd67bf2 100644
--- a/src/server/api/endpoints/i/authorized_apps.ts
+++ b/src/server/api/endpoints/i/authorized_apps.ts
@@ -10,15 +10,15 @@ import { pack } from '../../../../models/app';
  */
 module.exports = (params, user) => new Promise(async (res, rej) => {
 	// Get 'limit' parameter
-	const [limit = 10, limitErr] = $(params.limit).optional.number().range(1, 100).get();
+	const [limit = 10, limitErr] = $.num.optional().range(1, 100).get(params.limit);
 	if (limitErr) return rej('invalid limit param');
 
 	// Get 'offset' parameter
-	const [offset = 0, offsetErr] = $(params.offset).optional.number().min(0).get();
+	const [offset = 0, offsetErr] = $.num.optional().min(0).get(params.offset);
 	if (offsetErr) return rej('invalid offset param');
 
 	// Get 'sort' parameter
-	const [sort = 'desc', sortError] = $(params.sort).optional.string().or('desc asc').get();
+	const [sort = 'desc', sortError] = $.str.optional().or('desc asc').get(params.sort);
 	if (sortError) return rej('invalid sort param');
 
 	// Get tokens
diff --git a/src/server/api/endpoints/i/change_password.ts b/src/server/api/endpoints/i/change_password.ts
index 5c8c71d140..a1a1a43406 100644
--- a/src/server/api/endpoints/i/change_password.ts
+++ b/src/server/api/endpoints/i/change_password.ts
@@ -10,11 +10,11 @@ import User from '../../../../models/user';
  */
 module.exports = async (params, user) => new Promise(async (res, rej) => {
 	// Get 'currentPasword' parameter
-	const [currentPassword, currentPasswordErr] = $(params.currentPasword).string().get();
+	const [currentPassword, currentPasswordErr] = $.str.get(params.currentPasword);
 	if (currentPasswordErr) return rej('invalid currentPasword param');
 
 	// Get 'newPassword' parameter
-	const [newPassword, newPasswordErr] = $(params.newPassword).string().get();
+	const [newPassword, newPasswordErr] = $.str.get(params.newPassword);
 	if (newPasswordErr) return rej('invalid newPassword param');
 
 	// Compare password
diff --git a/src/server/api/endpoints/i/favorites.ts b/src/server/api/endpoints/i/favorites.ts
index a65f673a7d..23517baaff 100644
--- a/src/server/api/endpoints/i/favorites.ts
+++ b/src/server/api/endpoints/i/favorites.ts
@@ -9,15 +9,15 @@ import Favorite, { pack } from '../../../../models/favorite';
  */
 module.exports = (params, user) => new Promise(async (res, rej) => {
 	// Get 'limit' parameter
-	const [limit = 10, limitErr] = $(params.limit).optional.number().range(1, 100).get();
+	const [limit = 10, limitErr] = $.num.optional().range(1, 100).get(params.limit);
 	if (limitErr) return rej('invalid limit param');
 
 	// Get 'sinceId' parameter
-	const [sinceId, sinceIdErr] = $(params.sinceId).optional.type(ID).get();
+	const [sinceId, sinceIdErr] = $.type(ID).optional().get(params.sinceId);
 	if (sinceIdErr) return rej('invalid sinceId param');
 
 	// Get 'untilId' parameter
-	const [untilId, untilIdErr] = $(params.untilId).optional.type(ID).get();
+	const [untilId, untilIdErr] = $.type(ID).optional().get(params.untilId);
 	if (untilIdErr) return rej('invalid untilId param');
 
 	// Check if both of sinceId and untilId is specified
diff --git a/src/server/api/endpoints/i/notifications.ts b/src/server/api/endpoints/i/notifications.ts
index a0bf2338a6..50ed9b27e8 100644
--- a/src/server/api/endpoints/i/notifications.ts
+++ b/src/server/api/endpoints/i/notifications.ts
@@ -14,27 +14,27 @@ import read from '../../common/read-notification';
 module.exports = (params, user) => new Promise(async (res, rej) => {
 	// Get 'following' parameter
 	const [following = false, followingError] =
-		$(params.following).optional.boolean().get();
+		$.bool.optional().get(params.following);
 	if (followingError) return rej('invalid following param');
 
 	// Get 'markAsRead' parameter
-	const [markAsRead = true, markAsReadErr] = $(params.markAsRead).optional.boolean().get();
+	const [markAsRead = true, markAsReadErr] = $.bool.optional().get(params.markAsRead);
 	if (markAsReadErr) return rej('invalid markAsRead param');
 
 	// Get 'type' parameter
-	const [type, typeErr] = $(params.type).optional.array($().string()).unique().get();
+	const [type, typeErr] = $.arr($.str).optional().unique().get(params.type);
 	if (typeErr) return rej('invalid type param');
 
 	// Get 'limit' parameter
-	const [limit = 10, limitErr] = $(params.limit).optional.number().range(1, 100).get();
+	const [limit = 10, limitErr] = $.num.optional().range(1, 100).get(params.limit);
 	if (limitErr) return rej('invalid limit param');
 
 	// Get 'sinceId' parameter
-	const [sinceId, sinceIdErr] = $(params.sinceId).optional.type(ID).get();
+	const [sinceId, sinceIdErr] = $.type(ID).optional().get(params.sinceId);
 	if (sinceIdErr) return rej('invalid sinceId param');
 
 	// Get 'untilId' parameter
-	const [untilId, untilIdErr] = $(params.untilId).optional.type(ID).get();
+	const [untilId, untilIdErr] = $.type(ID).optional().get(params.untilId);
 	if (untilIdErr) return rej('invalid untilId param');
 
 	// Check if both of sinceId and untilId is specified
diff --git a/src/server/api/endpoints/i/pin.ts b/src/server/api/endpoints/i/pin.ts
index 1d995746dc..423f0ac4ae 100644
--- a/src/server/api/endpoints/i/pin.ts
+++ b/src/server/api/endpoints/i/pin.ts
@@ -11,7 +11,7 @@ import { pack } from '../../../../models/user';
  */
 module.exports = async (params, user) => new Promise(async (res, rej) => {
 	// Get 'noteId' parameter
-	const [noteId, noteIdErr] = $(params.noteId).type(ID).get();
+	const [noteId, noteIdErr] = $.type(ID).get(params.noteId);
 	if (noteIdErr) return rej('invalid noteId param');
 
 	// Fetch pinee
diff --git a/src/server/api/endpoints/i/regenerate_token.ts b/src/server/api/endpoints/i/regenerate_token.ts
index df440c68ab..6e1e571297 100644
--- a/src/server/api/endpoints/i/regenerate_token.ts
+++ b/src/server/api/endpoints/i/regenerate_token.ts
@@ -12,7 +12,7 @@ import generateUserToken from '../../common/generate-native-user-token';
  */
 module.exports = async (params, user) => new Promise(async (res, rej) => {
 	// Get 'password' parameter
-	const [password, passwordErr] = $(params.password).string().get();
+	const [password, passwordErr] = $.str.get(params.password);
 	if (passwordErr) return rej('invalid password param');
 
 	// Compare password
diff --git a/src/server/api/endpoints/i/signin_history.ts b/src/server/api/endpoints/i/signin_history.ts
index d505caad82..63a74b41b1 100644
--- a/src/server/api/endpoints/i/signin_history.ts
+++ b/src/server/api/endpoints/i/signin_history.ts
@@ -9,15 +9,15 @@ import Signin, { pack } from '../../../../models/signin';
  */
 module.exports = (params, user) => new Promise(async (res, rej) => {
 	// Get 'limit' parameter
-	const [limit = 10, limitErr] = $(params.limit).optional.number().range(1, 100).get();
+	const [limit = 10, limitErr] = $.num.optional().range(1, 100).get(params.limit);
 	if (limitErr) return rej('invalid limit param');
 
 	// Get 'sinceId' parameter
-	const [sinceId, sinceIdErr] = $(params.sinceId).optional.type(ID).get();
+	const [sinceId, sinceIdErr] = $.type(ID).optional().get(params.sinceId);
 	if (sinceIdErr) return rej('invalid sinceId param');
 
 	// Get 'untilId' parameter
-	const [untilId, untilIdErr] = $(params.untilId).optional.type(ID).get();
+	const [untilId, untilIdErr] = $.type(ID).optional().get(params.untilId);
 	if (untilIdErr) return rej('invalid untilId param');
 
 	// Check if both of sinceId and untilId is specified
diff --git a/src/server/api/endpoints/i/update.ts b/src/server/api/endpoints/i/update.ts
index 2b76497025..6ba4729951 100644
--- a/src/server/api/endpoints/i/update.ts
+++ b/src/server/api/endpoints/i/update.ts
@@ -12,42 +12,42 @@ module.exports = async (params, user, app) => new Promise(async (res, rej) => {
 	const isSecure = user != null && app == null;
 
 	// Get 'name' parameter
-	const [name, nameErr] = $(params.name).optional.nullable.string().pipe(isValidName).get();
+	const [name, nameErr] = $.str.optional().nullable().pipe(isValidName).get(params.name);
 	if (nameErr) return rej('invalid name param');
 	if (name) user.name = name;
 
 	// Get 'description' parameter
-	const [description, descriptionErr] = $(params.description).optional.nullable.string().pipe(isValidDescription).get();
+	const [description, descriptionErr] = $.str.optional().nullable().pipe(isValidDescription).get(params.description);
 	if (descriptionErr) return rej('invalid description param');
 	if (description !== undefined) user.description = description;
 
 	// Get 'location' parameter
-	const [location, locationErr] = $(params.location).optional.nullable.string().pipe(isValidLocation).get();
+	const [location, locationErr] = $.str.optional().nullable().pipe(isValidLocation).get(params.location);
 	if (locationErr) return rej('invalid location param');
 	if (location !== undefined) user.profile.location = location;
 
 	// Get 'birthday' parameter
-	const [birthday, birthdayErr] = $(params.birthday).optional.nullable.string().pipe(isValidBirthday).get();
+	const [birthday, birthdayErr] = $.str.optional().nullable().pipe(isValidBirthday).get(params.birthday);
 	if (birthdayErr) return rej('invalid birthday param');
 	if (birthday !== undefined) user.profile.birthday = birthday;
 
 	// Get 'avatarId' parameter
-	const [avatarId, avatarIdErr] = $(params.avatarId).optional.type(ID).get();
+	const [avatarId, avatarIdErr] = $.type(ID).optional().get(params.avatarId);
 	if (avatarIdErr) return rej('invalid avatarId param');
 	if (avatarId) user.avatarId = avatarId;
 
 	// Get 'bannerId' parameter
-	const [bannerId, bannerIdErr] = $(params.bannerId).optional.type(ID).get();
+	const [bannerId, bannerIdErr] = $.type(ID).optional().get(params.bannerId);
 	if (bannerIdErr) return rej('invalid bannerId param');
 	if (bannerId) user.bannerId = bannerId;
 
 	// Get 'isBot' parameter
-	const [isBot, isBotErr] = $(params.isBot).optional.boolean().get();
+	const [isBot, isBotErr] = $.bool.optional().get(params.isBot);
 	if (isBotErr) return rej('invalid isBot param');
 	if (isBot != null) user.isBot = isBot;
 
 	// Get 'autoWatch' parameter
-	const [autoWatch, autoWatchErr] = $(params.autoWatch).optional.boolean().get();
+	const [autoWatch, autoWatchErr] = $.bool.optional().get(params.autoWatch);
 	if (autoWatchErr) return rej('invalid autoWatch param');
 	if (autoWatch != null) user.settings.autoWatch = autoWatch;
 
diff --git a/src/server/api/endpoints/i/update_client_setting.ts b/src/server/api/endpoints/i/update_client_setting.ts
index 278eb1cbeb..e91d7565fd 100644
--- a/src/server/api/endpoints/i/update_client_setting.ts
+++ b/src/server/api/endpoints/i/update_client_setting.ts
@@ -2,7 +2,7 @@
  * Module dependencies
  */
 import $ from 'cafy';
-import User, { pack } from '../../../../models/user';
+import User from '../../../../models/user';
 import event from '../../../../publishers/stream';
 
 /**
@@ -10,11 +10,11 @@ import event from '../../../../publishers/stream';
  */
 module.exports = async (params, user) => new Promise(async (res, rej) => {
 	// Get 'name' parameter
-	const [name, nameErr] = $(params.name).string().get();
+	const [name, nameErr] = $.str.get(params.name);
 	if (nameErr) return rej('invalid name param');
 
 	// Get 'value' parameter
-	const [value, valueErr] = $(params.value).nullable.any().get();
+	const [value, valueErr] = $.any.nullable().get(params.value);
 	if (valueErr) return rej('invalid value param');
 
 	const x = {};
diff --git a/src/server/api/endpoints/i/update_home.ts b/src/server/api/endpoints/i/update_home.ts
index baf9b739ae..8ce551957e 100644
--- a/src/server/api/endpoints/i/update_home.ts
+++ b/src/server/api/endpoints/i/update_home.ts
@@ -7,20 +7,22 @@ import event from '../../../../publishers/stream';
 
 module.exports = async (params, user) => new Promise(async (res, rej) => {
 	// Get 'home' parameter
-	const [home, homeErr] = $(params.home).optional.array().each(
-		$().object(true)
-			.have('name', $().string())
-			.have('id', $().string())
-			.have('place', $().string())
-			.have('data', $().object())).get();
+	const [home, homeErr] = $.arr(
+		$.obj.strict()
+			.have('name', $.str)
+			.have('id', $.str)
+			.have('place', $.str)
+			.have('data', $.obj))
+		.optional()
+		.get(params.home);
 	if (homeErr) return rej('invalid home param');
 
 	// Get 'id' parameter
-	const [id, idErr] = $(params.id).optional.string().get();
+	const [id, idErr] = $.str.optional().get(params.id);
 	if (idErr) return rej('invalid id param');
 
 	// Get 'data' parameter
-	const [data, dataErr] = $(params.data).optional.object().get();
+	const [data, dataErr] = $.obj.optional().get(params.data);
 	if (dataErr) return rej('invalid data param');
 
 	if (home) {
diff --git a/src/server/api/endpoints/i/update_mobile_home.ts b/src/server/api/endpoints/i/update_mobile_home.ts
index 21d94839b7..d79a77072b 100644
--- a/src/server/api/endpoints/i/update_mobile_home.ts
+++ b/src/server/api/endpoints/i/update_mobile_home.ts
@@ -7,19 +7,20 @@ import event from '../../../../publishers/stream';
 
 module.exports = async (params, user) => new Promise(async (res, rej) => {
 	// Get 'home' parameter
-	const [home, homeErr] = $(params.home).optional.array().each(
-		$().object(true)
-			.have('name', $().string())
-			.have('id', $().string())
-			.have('data', $().object())).get();
+	const [home, homeErr] = $.arr(
+		$.obj.strict()
+			.have('name', $.str)
+			.have('id', $.str)
+			.have('data', $.obj))
+		.optional().get(params.home);
 	if (homeErr) return rej('invalid home param');
 
 	// Get 'id' parameter
-	const [id, idErr] = $(params.id).optional.string().get();
+	const [id, idErr] = $.str.optional().get(params.id);
 	if (idErr) return rej('invalid id param');
 
 	// Get 'data' parameter
-	const [data, dataErr] = $(params.data).optional.object().get();
+	const [data, dataErr] = $.obj.optional().get(params.data);
 	if (dataErr) return rej('invalid data param');
 
 	if (home) {
diff --git a/src/server/api/endpoints/messaging/history.ts b/src/server/api/endpoints/messaging/history.ts
index 9fd1f80d7b..ec97642f17 100644
--- a/src/server/api/endpoints/messaging/history.ts
+++ b/src/server/api/endpoints/messaging/history.ts
@@ -11,7 +11,7 @@ import { pack } from '../../../../models/messaging-message';
  */
 module.exports = (params, user) => new Promise(async (res, rej) => {
 	// Get 'limit' parameter
-	const [limit = 10, limitErr] = $(params.limit).optional.number().range(1, 100).get();
+	const [limit = 10, limitErr] = $.num.optional().range(1, 100).get(params.limit);
 	if (limitErr) return rej('invalid limit param');
 
 	const mute = await Mute.find({
diff --git a/src/server/api/endpoints/messaging/messages.ts b/src/server/api/endpoints/messaging/messages.ts
index f154133a12..0338aba68a 100644
--- a/src/server/api/endpoints/messaging/messages.ts
+++ b/src/server/api/endpoints/messaging/messages.ts
@@ -16,7 +16,7 @@ import read from '../../common/read-messaging-message';
  */
 module.exports = (params, user) => new Promise(async (res, rej) => {
 	// Get 'userId' parameter
-	const [recipientId, recipientIdErr] = $(params.userId).type(ID).get();
+	const [recipientId, recipientIdErr] = $.type(ID).get(params.userId);
 	if (recipientIdErr) return rej('invalid userId param');
 
 	// Fetch recipient
@@ -33,19 +33,19 @@ module.exports = (params, user) => new Promise(async (res, rej) => {
 	}
 
 	// Get 'markAsRead' parameter
-	const [markAsRead = true, markAsReadErr] = $(params.markAsRead).optional.boolean().get();
+	const [markAsRead = true, markAsReadErr] = $.bool.optional().get(params.markAsRead);
 	if (markAsReadErr) return rej('invalid markAsRead param');
 
 	// Get 'limit' parameter
-	const [limit = 10, limitErr] = $(params.limit).optional.number().range(1, 100).get();
+	const [limit = 10, limitErr] = $.num.optional().range(1, 100).get(params.limit);
 	if (limitErr) return rej('invalid limit param');
 
 	// Get 'sinceId' parameter
-	const [sinceId, sinceIdErr] = $(params.sinceId).optional.type(ID).get();
+	const [sinceId, sinceIdErr] = $.type(ID).optional().get(params.sinceId);
 	if (sinceIdErr) return rej('invalid sinceId param');
 
 	// Get 'untilId' parameter
-	const [untilId, untilIdErr] = $(params.untilId).optional.type(ID).get();
+	const [untilId, untilIdErr] = $.type(ID).optional().get(params.untilId);
 	if (untilIdErr) return rej('invalid untilId param');
 
 	// Check if both of sinceId and untilId is specified
diff --git a/src/server/api/endpoints/messaging/messages/create.ts b/src/server/api/endpoints/messaging/messages/create.ts
index 8b708eeaa9..db471839e7 100644
--- a/src/server/api/endpoints/messaging/messages/create.ts
+++ b/src/server/api/endpoints/messaging/messages/create.ts
@@ -19,7 +19,7 @@ import config from '../../../../../config';
  */
 module.exports = (params, user) => new Promise(async (res, rej) => {
 	// Get 'userId' parameter
-	const [recipientId, recipientIdErr] = $(params.userId).type(ID).get();
+	const [recipientId, recipientIdErr] = $.type(ID).get(params.userId);
 	if (recipientIdErr) return rej('invalid userId param');
 
 	// Myself
@@ -41,11 +41,11 @@ module.exports = (params, user) => new Promise(async (res, rej) => {
 	}
 
 	// Get 'text' parameter
-	const [text, textErr] = $(params.text).optional.string().pipe(isValidText).get();
+	const [text, textErr] = $.str.optional().pipe(isValidText).get(params.text);
 	if (textErr) return rej('invalid text');
 
 	// Get 'fileId' parameter
-	const [fileId, fileIdErr] = $(params.fileId).optional.type(ID).get();
+	const [fileId, fileIdErr] = $.type(ID).optional().get(params.fileId);
 	if (fileIdErr) return rej('invalid fileId param');
 
 	let file = null;
diff --git a/src/server/api/endpoints/mute/create.ts b/src/server/api/endpoints/mute/create.ts
index aa9f6eb731..534020c671 100644
--- a/src/server/api/endpoints/mute/create.ts
+++ b/src/server/api/endpoints/mute/create.ts
@@ -12,7 +12,7 @@ module.exports = (params, user) => new Promise(async (res, rej) => {
 	const muter = user;
 
 	// Get 'userId' parameter
-	const [userId, userIdErr] = $(params.userId).type(ID).get();
+	const [userId, userIdErr] = $.type(ID).get(params.userId);
 	if (userIdErr) return rej('invalid userId param');
 
 	// 自分自身
diff --git a/src/server/api/endpoints/mute/delete.ts b/src/server/api/endpoints/mute/delete.ts
index f24db6770d..949aff64ba 100644
--- a/src/server/api/endpoints/mute/delete.ts
+++ b/src/server/api/endpoints/mute/delete.ts
@@ -12,7 +12,7 @@ module.exports = (params, user) => new Promise(async (res, rej) => {
 	const muter = user;
 
 	// Get 'userId' parameter
-	const [userId, userIdErr] = $(params.userId).type(ID).get();
+	const [userId, userIdErr] = $.type(ID).get(params.userId);
 	if (userIdErr) return rej('invalid userId param');
 
 	// Check if the mutee is yourself
diff --git a/src/server/api/endpoints/mute/list.ts b/src/server/api/endpoints/mute/list.ts
index f7199db64e..cf89f7e959 100644
--- a/src/server/api/endpoints/mute/list.ts
+++ b/src/server/api/endpoints/mute/list.ts
@@ -11,15 +11,15 @@ import { getFriendIds } from '../../common/get-friends';
  */
 module.exports = (params, me) => new Promise(async (res, rej) => {
 	// Get 'iknow' parameter
-	const [iknow = false, iknowErr] = $(params.iknow).optional.boolean().get();
+	const [iknow = false, iknowErr] = $.bool.optional().get(params.iknow);
 	if (iknowErr) return rej('invalid iknow param');
 
 	// Get 'limit' parameter
-	const [limit = 30, limitErr] = $(params.limit).optional.number().range(1, 100).get();
+	const [limit = 30, limitErr] = $.num.optional().range(1, 100).get(params.limit);
 	if (limitErr) return rej('invalid limit param');
 
 	// Get 'cursor' parameter
-	const [cursor = null, cursorErr] = $(params.cursor).optional.type(ID).get();
+	const [cursor = null, cursorErr] = $.type(ID).optional().get(params.cursor);
 	if (cursorErr) return rej('invalid cursor param');
 
 	// Construct query
diff --git a/src/server/api/endpoints/my/apps.ts b/src/server/api/endpoints/my/apps.ts
index 3b58b30241..086e0b8965 100644
--- a/src/server/api/endpoints/my/apps.ts
+++ b/src/server/api/endpoints/my/apps.ts
@@ -9,11 +9,11 @@ import App, { pack } from '../../../../models/app';
  */
 module.exports = (params, user) => new Promise(async (res, rej) => {
 	// Get 'limit' parameter
-	const [limit = 10, limitErr] = $(params.limit).optional.number().range(1, 100).get();
+	const [limit = 10, limitErr] = $.num.optional().range(1, 100).get(params.limit);
 	if (limitErr) return rej('invalid limit param');
 
 	// Get 'offset' parameter
-	const [offset = 0, offsetErr] = $(params.offset).optional.number().min(0).get();
+	const [offset = 0, offsetErr] = $.num.optional().min(0).get(params.offset);
 	if (offsetErr) return rej('invalid offset param');
 
 	const query = {
diff --git a/src/server/api/endpoints/notes.ts b/src/server/api/endpoints/notes.ts
index 7be35961d2..4ce7613d70 100644
--- a/src/server/api/endpoints/notes.ts
+++ b/src/server/api/endpoints/notes.ts
@@ -9,35 +9,35 @@ import Note, { pack } from '../../../models/note';
  */
 module.exports = (params) => new Promise(async (res, rej) => {
 	// Get 'reply' parameter
-	const [reply, replyErr] = $(params.reply).optional.boolean().get();
+	const [reply, replyErr] = $.bool.optional().get(params.reply);
 	if (replyErr) return rej('invalid reply param');
 
 	// Get 'renote' parameter
-	const [renote, renoteErr] = $(params.renote).optional.boolean().get();
+	const [renote, renoteErr] = $.bool.optional().get(params.renote);
 	if (renoteErr) return rej('invalid renote param');
 
 	// Get 'media' parameter
-	const [media, mediaErr] = $(params.media).optional.boolean().get();
+	const [media, mediaErr] = $.bool.optional().get(params.media);
 	if (mediaErr) return rej('invalid media param');
 
 	// Get 'poll' parameter
-	const [poll, pollErr] = $(params.poll).optional.boolean().get();
+	const [poll, pollErr] = $.bool.optional().get(params.poll);
 	if (pollErr) return rej('invalid poll param');
 
 	// Get 'bot' parameter
-	//const [bot, botErr] = $(params.bot).optional.boolean().get();
+	//const [bot, botErr] = $.bool.optional().get(params.bot);
 	//if (botErr) return rej('invalid bot param');
 
 	// Get 'limit' parameter
-	const [limit = 10, limitErr] = $(params.limit).optional.number().range(1, 100).get();
+	const [limit = 10, limitErr] = $.num.optional().range(1, 100).get(params.limit);
 	if (limitErr) return rej('invalid limit param');
 
 	// Get 'sinceId' parameter
-	const [sinceId, sinceIdErr] = $(params.sinceId).optional.type(ID).get();
+	const [sinceId, sinceIdErr] = $.type(ID).optional().get(params.sinceId);
 	if (sinceIdErr) return rej('invalid sinceId param');
 
 	// Get 'untilId' parameter
-	const [untilId, untilIdErr] = $(params.untilId).optional.type(ID).get();
+	const [untilId, untilIdErr] = $.type(ID).optional().get(params.untilId);
 	if (untilIdErr) return rej('invalid untilId param');
 
 	// Check if both of sinceId and untilId is specified
diff --git a/src/server/api/endpoints/notes/context.ts b/src/server/api/endpoints/notes/context.ts
index 7e3533cfd8..1cd27250e2 100644
--- a/src/server/api/endpoints/notes/context.ts
+++ b/src/server/api/endpoints/notes/context.ts
@@ -13,15 +13,15 @@ import Note, { pack } from '../../../../models/note';
  */
 module.exports = (params, user) => new Promise(async (res, rej) => {
 	// Get 'noteId' parameter
-	const [noteId, noteIdErr] = $(params.noteId).type(ID).get();
+	const [noteId, noteIdErr] = $.type(ID).get(params.noteId);
 	if (noteIdErr) return rej('invalid noteId param');
 
 	// Get 'limit' parameter
-	const [limit = 10, limitErr] = $(params.limit).optional.number().range(1, 100).get();
+	const [limit = 10, limitErr] = $.num.optional().range(1, 100).get(params.limit);
 	if (limitErr) return rej('invalid limit param');
 
 	// Get 'offset' parameter
-	const [offset = 0, offsetErr] = $(params.offset).optional.number().min(0).get();
+	const [offset = 0, offsetErr] = $.num.optional().min(0).get(params.offset);
 	if (offsetErr) return rej('invalid offset param');
 
 	// Lookup note
diff --git a/src/server/api/endpoints/notes/create.ts b/src/server/api/endpoints/notes/create.ts
index 52c6068fd0..fe947174d1 100644
--- a/src/server/api/endpoints/notes/create.ts
+++ b/src/server/api/endpoints/notes/create.ts
@@ -14,11 +14,11 @@ import { IApp } from '../../../../models/app';
  */
 module.exports = (params, user: ILocalUser, app: IApp) => new Promise(async (res, rej) => {
 	// Get 'visibility' parameter
-	const [visibility = 'public', visibilityErr] = $(params.visibility).optional.string().or(['public', 'home', 'followers', 'specified', 'private']).get();
+	const [visibility = 'public', visibilityErr] = $.str.optional().or(['public', 'home', 'followers', 'specified', 'private']).get(params.visibility);
 	if (visibilityErr) return rej('invalid visibility');
 
 	// Get 'visibleUserIds' parameter
-	const [visibleUserIds, visibleUserIdsErr] = $(params.visibleUserIds).optional.array($().type(ID)).unique().min(1).get();
+	const [visibleUserIds, visibleUserIdsErr] = $.arr($.type(ID)).optional().unique().min(1).get(params.visibleUserIds);
 	if (visibleUserIdsErr) return rej('invalid visibleUserIds');
 
 	let visibleUsers = [];
@@ -29,36 +29,36 @@ module.exports = (params, user: ILocalUser, app: IApp) => new Promise(async (res
 	}
 
 	// Get 'text' parameter
-	const [text = null, textErr] = $(params.text).optional.nullable.string().pipe(isValidText).get();
+	const [text = null, textErr] = $.str.optional().nullable().pipe(isValidText).get(params.text);
 	if (textErr) return rej('invalid text');
 
 	// Get 'cw' parameter
-	const [cw, cwErr] = $(params.cw).optional.nullable.string().pipe(isValidCw).get();
+	const [cw, cwErr] = $.str.optional().nullable().pipe(isValidCw).get(params.cw);
 	if (cwErr) return rej('invalid cw');
 
 	// Get 'viaMobile' parameter
-	const [viaMobile = false, viaMobileErr] = $(params.viaMobile).optional.boolean().get();
+	const [viaMobile = false, viaMobileErr] = $.bool.optional().get(params.viaMobile);
 	if (viaMobileErr) return rej('invalid viaMobile');
 
 	// Get 'tags' parameter
-	const [tags = [], tagsErr] = $(params.tags).optional.array($().string().range(1, 32)).unique().get();
+	const [tags = [], tagsErr] = $.arr($.str.optional().range(1, 32)).unique().get(params.tags);
 	if (tagsErr) return rej('invalid tags');
 
 	// Get 'geo' parameter
-	const [geo, geoErr] = $(params.geo).optional.nullable.object(true)
-		.have('coordinates', $().array().length(2)
-			.item(0, $().number().range(-180, 180))
-			.item(1, $().number().range(-90, 90)))
-		.have('altitude', $().nullable.number())
-		.have('accuracy', $().nullable.number())
-		.have('altitudeAccuracy', $().nullable.number())
-		.have('heading', $().nullable.number().range(0, 360))
-		.have('speed', $().nullable.number())
-		.get();
+	const [geo, geoErr] = $.obj.optional().nullable().strict()
+		.have('coordinates', $.arr().length(2)
+			.item(0, $.num.range(-180, 180))
+			.item(1, $.num.range(-90, 90)))
+		.have('altitude', $.num.nullable())
+		.have('accuracy', $.num.nullable())
+		.have('altitudeAccuracy', $.num.nullable())
+		.have('heading', $.num.nullable().range(0, 360))
+		.have('speed', $.num.nullable())
+		.get(params.geo);
 	if (geoErr) return rej('invalid geo');
 
 	// Get 'mediaIds' parameter
-	const [mediaIds, mediaIdsErr] = $(params.mediaIds).optional.array($().type(ID)).unique().range(1, 4).get();
+	const [mediaIds, mediaIdsErr] = $.arr($.type(ID)).optional().unique().range(1, 4).get(params.mediaIds);
 	if (mediaIdsErr) return rej('invalid mediaIds');
 
 	let files = [];
@@ -85,7 +85,7 @@ module.exports = (params, user: ILocalUser, app: IApp) => new Promise(async (res
 	}
 
 	// Get 'renoteId' parameter
-	const [renoteId, renoteIdErr] = $(params.renoteId).optional.type(ID).get();
+	const [renoteId, renoteIdErr] = $.type(ID).optional().get(params.renoteId);
 	if (renoteIdErr) return rej('invalid renoteId');
 
 	let renote: INote = null;
@@ -106,7 +106,7 @@ module.exports = (params, user: ILocalUser, app: IApp) => new Promise(async (res
 	}
 
 	// Get 'replyId' parameter
-	const [replyId, replyIdErr] = $(params.replyId).optional.type(ID).get();
+	const [replyId, replyIdErr] = $.type(ID).optional().get(params.replyId);
 	if (replyIdErr) return rej('invalid replyId');
 
 	let reply: INote = null;
@@ -127,7 +127,7 @@ module.exports = (params, user: ILocalUser, app: IApp) => new Promise(async (res
 	}
 
 	// Get 'channelId' parameter
-	const [channelId, channelIdErr] = $(params.channelId).optional.type(ID).get();
+	const [channelId, channelIdErr] = $.type(ID).optional().get(params.channelId);
 	if (channelIdErr) return rej('invalid channelId');
 
 	let channel: IChannel = null;
@@ -168,12 +168,12 @@ module.exports = (params, user: ILocalUser, app: IApp) => new Promise(async (res
 	}
 
 	// Get 'poll' parameter
-	const [poll, pollErr] = $(params.poll).optional.object(true)
-		.have('choices', $().array($().string())
+	const [poll, pollErr] = $.obj.optional().strict()
+		.have('choices', $.arr($.str)
 			.unique()
 			.range(2, 10)
 			.each(c => c.length > 0 && c.length < 50))
-		.get();
+		.get(params.poll);
 	if (pollErr) return rej('invalid poll');
 
 	if (poll) {
diff --git a/src/server/api/endpoints/notes/favorites/create.ts b/src/server/api/endpoints/notes/favorites/create.ts
index e6396b85ce..6832b52f75 100644
--- a/src/server/api/endpoints/notes/favorites/create.ts
+++ b/src/server/api/endpoints/notes/favorites/create.ts
@@ -10,7 +10,7 @@ import Note from '../../../../../models/note';
  */
 module.exports = (params, user) => new Promise(async (res, rej) => {
 	// Get 'noteId' parameter
-	const [noteId, noteIdErr] = $(params.noteId).type(ID).get();
+	const [noteId, noteIdErr] = $.type(ID).get(params.noteId);
 	if (noteIdErr) return rej('invalid noteId param');
 
 	// Get favoritee
diff --git a/src/server/api/endpoints/notes/favorites/delete.ts b/src/server/api/endpoints/notes/favorites/delete.ts
index f1de424725..07112dae15 100644
--- a/src/server/api/endpoints/notes/favorites/delete.ts
+++ b/src/server/api/endpoints/notes/favorites/delete.ts
@@ -10,7 +10,7 @@ import Note from '../../../../../models/note';
  */
 module.exports = (params, user) => new Promise(async (res, rej) => {
 	// Get 'noteId' parameter
-	const [noteId, noteIdErr] = $(params.noteId).type(ID).get();
+	const [noteId, noteIdErr] = $.type(ID).get(params.noteId);
 	if (noteIdErr) return rej('invalid noteId param');
 
 	// Get favoritee
diff --git a/src/server/api/endpoints/notes/global-timeline.ts b/src/server/api/endpoints/notes/global-timeline.ts
index 212345aac0..d22a1763de 100644
--- a/src/server/api/endpoints/notes/global-timeline.ts
+++ b/src/server/api/endpoints/notes/global-timeline.ts
@@ -11,23 +11,23 @@ import { pack } from '../../../../models/note';
  */
 module.exports = async (params, user, app) => {
 	// Get 'limit' parameter
-	const [limit = 10, limitErr] = $(params.limit).optional.number().range(1, 100).get();
+	const [limit = 10, limitErr] = $.num.optional().range(1, 100).get(params.limit);
 	if (limitErr) throw 'invalid limit param';
 
 	// Get 'sinceId' parameter
-	const [sinceId, sinceIdErr] = $(params.sinceId).optional.type(ID).get();
+	const [sinceId, sinceIdErr] = $.type(ID).optional().get(params.sinceId);
 	if (sinceIdErr) throw 'invalid sinceId param';
 
 	// Get 'untilId' parameter
-	const [untilId, untilIdErr] = $(params.untilId).optional.type(ID).get();
+	const [untilId, untilIdErr] = $.type(ID).optional().get(params.untilId);
 	if (untilIdErr) throw 'invalid untilId param';
 
 	// Get 'sinceDate' parameter
-	const [sinceDate, sinceDateErr] = $(params.sinceDate).optional.number().get();
+	const [sinceDate, sinceDateErr] = $.num.optional().get(params.sinceDate);
 	if (sinceDateErr) throw 'invalid sinceDate param';
 
 	// Get 'untilDate' parameter
-	const [untilDate, untilDateErr] = $(params.untilDate).optional.number().get();
+	const [untilDate, untilDateErr] = $.num.optional().get(params.untilDate);
 	if (untilDateErr) throw 'invalid untilDate param';
 
 	// Check if only one of sinceId, untilId, sinceDate, untilDate specified
diff --git a/src/server/api/endpoints/notes/local-timeline.ts b/src/server/api/endpoints/notes/local-timeline.ts
index 12dd2d5a85..e7ebe5d960 100644
--- a/src/server/api/endpoints/notes/local-timeline.ts
+++ b/src/server/api/endpoints/notes/local-timeline.ts
@@ -11,23 +11,23 @@ import { pack } from '../../../../models/note';
  */
 module.exports = async (params, user, app) => {
 	// Get 'limit' parameter
-	const [limit = 10, limitErr] = $(params.limit).optional.number().range(1, 100).get();
+	const [limit = 10, limitErr] = $.num.optional().range(1, 100).get(params.limit);
 	if (limitErr) throw 'invalid limit param';
 
 	// Get 'sinceId' parameter
-	const [sinceId, sinceIdErr] = $(params.sinceId).optional.type(ID).get();
+	const [sinceId, sinceIdErr] = $.type(ID).optional().get(params.sinceId);
 	if (sinceIdErr) throw 'invalid sinceId param';
 
 	// Get 'untilId' parameter
-	const [untilId, untilIdErr] = $(params.untilId).optional.type(ID).get();
+	const [untilId, untilIdErr] = $.type(ID).optional().get(params.untilId);
 	if (untilIdErr) throw 'invalid untilId param';
 
 	// Get 'sinceDate' parameter
-	const [sinceDate, sinceDateErr] = $(params.sinceDate).optional.number().get();
+	const [sinceDate, sinceDateErr] = $.num.optional().get(params.sinceDate);
 	if (sinceDateErr) throw 'invalid sinceDate param';
 
 	// Get 'untilDate' parameter
-	const [untilDate, untilDateErr] = $(params.untilDate).optional.number().get();
+	const [untilDate, untilDateErr] = $.num.optional().get(params.untilDate);
 	if (untilDateErr) throw 'invalid untilDate param';
 
 	// Check if only one of sinceId, untilId, sinceDate, untilDate specified
diff --git a/src/server/api/endpoints/notes/mentions.ts b/src/server/api/endpoints/notes/mentions.ts
index db7c630897..163a6b4866 100644
--- a/src/server/api/endpoints/notes/mentions.ts
+++ b/src/server/api/endpoints/notes/mentions.ts
@@ -16,19 +16,19 @@ import { pack } from '../../../../models/note';
 module.exports = (params, user) => new Promise(async (res, rej) => {
 	// Get 'following' parameter
 	const [following = false, followingError] =
-		$(params.following).optional.boolean().get();
+		$.bool.optional().get(params.following);
 	if (followingError) return rej('invalid following param');
 
 	// Get 'limit' parameter
-	const [limit = 10, limitErr] = $(params.limit).optional.number().range(1, 100).get();
+	const [limit = 10, limitErr] = $.num.optional().range(1, 100).get(params.limit);
 	if (limitErr) return rej('invalid limit param');
 
 	// Get 'sinceId' parameter
-	const [sinceId, sinceIdErr] = $(params.sinceId).optional.type(ID).get();
+	const [sinceId, sinceIdErr] = $.type(ID).optional().get(params.sinceId);
 	if (sinceIdErr) return rej('invalid sinceId param');
 
 	// Get 'untilId' parameter
-	const [untilId, untilIdErr] = $(params.untilId).optional.type(ID).get();
+	const [untilId, untilIdErr] = $.type(ID).optional().get(params.untilId);
 	if (untilIdErr) return rej('invalid untilId param');
 
 	// Check if both of sinceId and untilId is specified
diff --git a/src/server/api/endpoints/notes/polls/recommendation.ts b/src/server/api/endpoints/notes/polls/recommendation.ts
index 1994c5ce7a..a272378d19 100644
--- a/src/server/api/endpoints/notes/polls/recommendation.ts
+++ b/src/server/api/endpoints/notes/polls/recommendation.ts
@@ -10,11 +10,11 @@ import Note, { pack } from '../../../../../models/note';
  */
 module.exports = (params, user) => new Promise(async (res, rej) => {
 	// Get 'limit' parameter
-	const [limit = 10, limitErr] = $(params.limit).optional.number().range(1, 100).get();
+	const [limit = 10, limitErr] = $.num.optional().range(1, 100).get(params.limit);
 	if (limitErr) return rej('invalid limit param');
 
 	// Get 'offset' parameter
-	const [offset = 0, offsetErr] = $(params.offset).optional.number().min(0).get();
+	const [offset = 0, offsetErr] = $.num.optional().min(0).get(params.offset);
 	if (offsetErr) return rej('invalid offset param');
 
 	// Get votes
diff --git a/src/server/api/endpoints/notes/polls/vote.ts b/src/server/api/endpoints/notes/polls/vote.ts
index 1915e0c79b..f8f4515308 100644
--- a/src/server/api/endpoints/notes/polls/vote.ts
+++ b/src/server/api/endpoints/notes/polls/vote.ts
@@ -14,7 +14,7 @@ import notify from '../../../../../publishers/notify';
  */
 module.exports = (params, user) => new Promise(async (res, rej) => {
 	// Get 'noteId' parameter
-	const [noteId, noteIdErr] = $(params.noteId).type(ID).get();
+	const [noteId, noteIdErr] = $.type(ID).get(params.noteId);
 	if (noteIdErr) return rej('invalid noteId param');
 
 	// Get votee
@@ -32,9 +32,9 @@ module.exports = (params, user) => new Promise(async (res, rej) => {
 
 	// Get 'choice' parameter
 	const [choice, choiceError] =
-		$(params.choice).number()
+		$.num
 			.pipe(c => note.poll.choices.some(x => x.id == c))
-			.get();
+			.get(params.choice);
 	if (choiceError) return rej('invalid choice param');
 
 	// if already voted
diff --git a/src/server/api/endpoints/notes/reactions.ts b/src/server/api/endpoints/notes/reactions.ts
index 75ed580de2..4ad952a7a1 100644
--- a/src/server/api/endpoints/notes/reactions.ts
+++ b/src/server/api/endpoints/notes/reactions.ts
@@ -14,19 +14,19 @@ import Reaction, { pack } from '../../../../models/note-reaction';
  */
 module.exports = (params, user) => new Promise(async (res, rej) => {
 	// Get 'noteId' parameter
-	const [noteId, noteIdErr] = $(params.noteId).type(ID).get();
+	const [noteId, noteIdErr] = $.type(ID).get(params.noteId);
 	if (noteIdErr) return rej('invalid noteId param');
 
 	// Get 'limit' parameter
-	const [limit = 10, limitErr] = $(params.limit).optional.number().range(1, 100).get();
+	const [limit = 10, limitErr] = $.num.optional().range(1, 100).get(params.limit);
 	if (limitErr) return rej('invalid limit param');
 
 	// Get 'offset' parameter
-	const [offset = 0, offsetErr] = $(params.offset).optional.number().min(0).get();
+	const [offset = 0, offsetErr] = $.num.optional().min(0).get(params.offset);
 	if (offsetErr) return rej('invalid offset param');
 
 	// Get 'sort' parameter
-	const [sort = 'desc', sortError] = $(params.sort).optional.string().or('desc asc').get();
+	const [sort = 'desc', sortError] = $.str.optional().or('desc asc').get(params.sort);
 	if (sortError) return rej('invalid sort param');
 
 	// Lookup note
diff --git a/src/server/api/endpoints/notes/reactions/create.ts b/src/server/api/endpoints/notes/reactions/create.ts
index 9dc1b3c82a..21757cb427 100644
--- a/src/server/api/endpoints/notes/reactions/create.ts
+++ b/src/server/api/endpoints/notes/reactions/create.ts
@@ -11,11 +11,11 @@ import { validateReaction } from '../../../../../models/note-reaction';
  */
 module.exports = (params, user) => new Promise(async (res, rej) => {
 	// Get 'noteId' parameter
-	const [noteId, noteIdErr] = $(params.noteId).type(ID).get();
+	const [noteId, noteIdErr] = $.type(ID).get(params.noteId);
 	if (noteIdErr) return rej('invalid noteId param');
 
 	// Get 'reaction' parameter
-	const [reaction, reactionErr] = $(params.reaction).string().pipe(validateReaction.ok).get();
+	const [reaction, reactionErr] = $.str.pipe(validateReaction.ok).get(params.reaction);
 	if (reactionErr) return rej('invalid reaction param');
 
 	// Fetch reactee
diff --git a/src/server/api/endpoints/notes/reactions/delete.ts b/src/server/api/endpoints/notes/reactions/delete.ts
index 6bd5edef42..afb8629112 100644
--- a/src/server/api/endpoints/notes/reactions/delete.ts
+++ b/src/server/api/endpoints/notes/reactions/delete.ts
@@ -10,7 +10,7 @@ import Note from '../../../../../models/note';
  */
 module.exports = (params, user) => new Promise(async (res, rej) => {
 	// Get 'noteId' parameter
-	const [noteId, noteIdErr] = $(params.noteId).type(ID).get();
+	const [noteId, noteIdErr] = $.type(ID).get(params.noteId);
 	if (noteIdErr) return rej('invalid noteId param');
 
 	// Fetch unreactee
diff --git a/src/server/api/endpoints/notes/replies.ts b/src/server/api/endpoints/notes/replies.ts
index 47c9ae501f..11d221d8f7 100644
--- a/src/server/api/endpoints/notes/replies.ts
+++ b/src/server/api/endpoints/notes/replies.ts
@@ -13,19 +13,19 @@ import Note, { pack } from '../../../../models/note';
  */
 module.exports = (params, user) => new Promise(async (res, rej) => {
 	// Get 'noteId' parameter
-	const [noteId, noteIdErr] = $(params.noteId).type(ID).get();
+	const [noteId, noteIdErr] = $.type(ID).get(params.noteId);
 	if (noteIdErr) return rej('invalid noteId param');
 
 	// Get 'limit' parameter
-	const [limit = 10, limitErr] = $(params.limit).optional.number().range(1, 100).get();
+	const [limit = 10, limitErr] = $.num.optional().range(1, 100).get(params.limit);
 	if (limitErr) return rej('invalid limit param');
 
 	// Get 'offset' parameter
-	const [offset = 0, offsetErr] = $(params.offset).optional.number().min(0).get();
+	const [offset = 0, offsetErr] = $.num.optional().min(0).get(params.offset);
 	if (offsetErr) return rej('invalid offset param');
 
 	// Get 'sort' parameter
-	const [sort = 'desc', sortError] = $(params.sort).optional.string().or('desc asc').get();
+	const [sort = 'desc', sortError] = $.str.optional().or('desc asc').get(params.sort);
 	if (sortError) return rej('invalid sort param');
 
 	// Lookup note
diff --git a/src/server/api/endpoints/notes/reposts.ts b/src/server/api/endpoints/notes/reposts.ts
index b388ee599f..3098211b61 100644
--- a/src/server/api/endpoints/notes/reposts.ts
+++ b/src/server/api/endpoints/notes/reposts.ts
@@ -13,19 +13,19 @@ import Note, { pack } from '../../../../models/note';
  */
 module.exports = (params, user) => new Promise(async (res, rej) => {
 	// Get 'noteId' parameter
-	const [noteId, noteIdErr] = $(params.noteId).type(ID).get();
+	const [noteId, noteIdErr] = $.type(ID).get(params.noteId);
 	if (noteIdErr) return rej('invalid noteId param');
 
 	// Get 'limit' parameter
-	const [limit = 10, limitErr] = $(params.limit).optional.number().range(1, 100).get();
+	const [limit = 10, limitErr] = $.num.optional().range(1, 100).get(params.limit);
 	if (limitErr) return rej('invalid limit param');
 
 	// Get 'sinceId' parameter
-	const [sinceId, sinceIdErr] = $(params.sinceId).optional.type(ID).get();
+	const [sinceId, sinceIdErr] = $.type(ID).optional().get(params.sinceId);
 	if (sinceIdErr) return rej('invalid sinceId param');
 
 	// Get 'untilId' parameter
-	const [untilId, untilIdErr] = $(params.untilId).optional.type(ID).get();
+	const [untilId, untilIdErr] = $.type(ID).optional().get(params.untilId);
 	if (untilIdErr) return rej('invalid untilId param');
 
 	// Check if both of sinceId and untilId is specified
diff --git a/src/server/api/endpoints/notes/search.ts b/src/server/api/endpoints/notes/search.ts
index 8b3c78145d..9705dcfd6e 100644
--- a/src/server/api/endpoints/notes/search.ts
+++ b/src/server/api/endpoints/notes/search.ts
@@ -18,63 +18,63 @@ import { pack } from '../../../../models/note';
  */
 module.exports = (params, me) => new Promise(async (res, rej) => {
 	// Get 'text' parameter
-	const [text, textError] = $(params.text).optional.string().get();
+	const [text, textError] = $.str.optional().get(params.text);
 	if (textError) return rej('invalid text param');
 
 	// Get 'includeUserIds' parameter
-	const [includeUserIds = [], includeUserIdsErr] = $(params.includeUserIds).optional.array($().type(ID)).get();
+	const [includeUserIds = [], includeUserIdsErr] = $.arr($.type(ID)).optional().get(params.includeUserIds);
 	if (includeUserIdsErr) return rej('invalid includeUserIds param');
 
 	// Get 'excludeUserIds' parameter
-	const [excludeUserIds = [], excludeUserIdsErr] = $(params.excludeUserIds).optional.array($().type(ID)).get();
+	const [excludeUserIds = [], excludeUserIdsErr] = $.arr($.type(ID)).optional().get(params.excludeUserIds);
 	if (excludeUserIdsErr) return rej('invalid excludeUserIds param');
 
 	// Get 'includeUserUsernames' parameter
-	const [includeUserUsernames = [], includeUserUsernamesErr] = $(params.includeUserUsernames).optional.array($().string()).get();
+	const [includeUserUsernames = [], includeUserUsernamesErr] = $.arr($.str).optional().get(params.includeUserUsernames);
 	if (includeUserUsernamesErr) return rej('invalid includeUserUsernames param');
 
 	// Get 'excludeUserUsernames' parameter
-	const [excludeUserUsernames = [], excludeUserUsernamesErr] = $(params.excludeUserUsernames).optional.array($().string()).get();
+	const [excludeUserUsernames = [], excludeUserUsernamesErr] = $.arr($.str).optional().get(params.excludeUserUsernames);
 	if (excludeUserUsernamesErr) return rej('invalid excludeUserUsernames param');
 
 	// Get 'following' parameter
-	const [following = null, followingErr] = $(params.following).optional.nullable.boolean().get();
+	const [following = null, followingErr] = $.bool.optional().nullable().get(params.following);
 	if (followingErr) return rej('invalid following param');
 
 	// Get 'mute' parameter
-	const [mute = 'mute_all', muteErr] = $(params.mute).optional.string().get();
+	const [mute = 'mute_all', muteErr] = $.str.optional().get(params.mute);
 	if (muteErr) return rej('invalid mute param');
 
 	// Get 'reply' parameter
-	const [reply = null, replyErr] = $(params.reply).optional.nullable.boolean().get();
+	const [reply = null, replyErr] = $.bool.optional().nullable().get(params.reply);
 	if (replyErr) return rej('invalid reply param');
 
 	// Get 'renote' parameter
-	const [renote = null, renoteErr] = $(params.renote).optional.nullable.boolean().get();
+	const [renote = null, renoteErr] = $.bool.optional().nullable().get(params.renote);
 	if (renoteErr) return rej('invalid renote param');
 
 	// Get 'media' parameter
-	const [media = null, mediaErr] = $(params.media).optional.nullable.boolean().get();
+	const [media = null, mediaErr] = $.bool.optional().nullable().get(params.media);
 	if (mediaErr) return rej('invalid media param');
 
 	// Get 'poll' parameter
-	const [poll = null, pollErr] = $(params.poll).optional.nullable.boolean().get();
+	const [poll = null, pollErr] = $.bool.optional().nullable().get(params.poll);
 	if (pollErr) return rej('invalid poll param');
 
 	// Get 'sinceDate' parameter
-	const [sinceDate, sinceDateErr] = $(params.sinceDate).optional.number().get();
+	const [sinceDate, sinceDateErr] = $.num.optional().get(params.sinceDate);
 	if (sinceDateErr) throw 'invalid sinceDate param';
 
 	// Get 'untilDate' parameter
-	const [untilDate, untilDateErr] = $(params.untilDate).optional.number().get();
+	const [untilDate, untilDateErr] = $.num.optional().get(params.untilDate);
 	if (untilDateErr) throw 'invalid untilDate param';
 
 	// Get 'offset' parameter
-	const [offset = 0, offsetErr] = $(params.offset).optional.number().min(0).get();
+	const [offset = 0, offsetErr] = $.num.optional().min(0).get(params.offset);
 	if (offsetErr) return rej('invalid offset param');
 
 	// Get 'limit' parameter
-	const [limit = 10, limitErr] = $(params.limit).optional.number().range(1, 30).get();
+	const [limit = 10, limitErr] = $.num.optional().range(1, 30).get(params.limit);
 	if (limitErr) return rej('invalid limit param');
 
 	let includeUsers = includeUserIds;
diff --git a/src/server/api/endpoints/notes/show.ts b/src/server/api/endpoints/notes/show.ts
index 2a4f8f97e1..78dc55a703 100644
--- a/src/server/api/endpoints/notes/show.ts
+++ b/src/server/api/endpoints/notes/show.ts
@@ -13,7 +13,7 @@ import Note, { pack } from '../../../../models/note';
  */
 module.exports = (params, user) => new Promise(async (res, rej) => {
 	// Get 'noteId' parameter
-	const [noteId, noteIdErr] = $(params.noteId).type(ID).get();
+	const [noteId, noteIdErr] = $.type(ID).get(params.noteId);
 	if (noteIdErr) return rej('invalid noteId param');
 
 	// Get note
diff --git a/src/server/api/endpoints/notes/timeline.ts b/src/server/api/endpoints/notes/timeline.ts
index 222f0b795f..78786d4a16 100644
--- a/src/server/api/endpoints/notes/timeline.ts
+++ b/src/server/api/endpoints/notes/timeline.ts
@@ -13,23 +13,23 @@ import { pack } from '../../../../models/note';
  */
 module.exports = async (params, user, app) => {
 	// Get 'limit' parameter
-	const [limit = 10, limitErr] = $(params.limit).optional.number().range(1, 100).get();
+	const [limit = 10, limitErr] = $.num.optional().range(1, 100).get(params.limit);
 	if (limitErr) throw 'invalid limit param';
 
 	// Get 'sinceId' parameter
-	const [sinceId, sinceIdErr] = $(params.sinceId).optional.type(ID).get();
+	const [sinceId, sinceIdErr] = $.type(ID).optional().get(params.sinceId);
 	if (sinceIdErr) throw 'invalid sinceId param';
 
 	// Get 'untilId' parameter
-	const [untilId, untilIdErr] = $(params.untilId).optional.type(ID).get();
+	const [untilId, untilIdErr] = $.type(ID).optional().get(params.untilId);
 	if (untilIdErr) throw 'invalid untilId param';
 
 	// Get 'sinceDate' parameter
-	const [sinceDate, sinceDateErr] = $(params.sinceDate).optional.number().get();
+	const [sinceDate, sinceDateErr] = $.num.optional().get(params.sinceDate);
 	if (sinceDateErr) throw 'invalid sinceDate param';
 
 	// Get 'untilDate' parameter
-	const [untilDate, untilDateErr] = $(params.untilDate).optional.number().get();
+	const [untilDate, untilDateErr] = $.num.optional().get(params.untilDate);
 	if (untilDateErr) throw 'invalid untilDate param';
 
 	// Check if only one of sinceId, untilId, sinceDate, untilDate specified
@@ -38,11 +38,11 @@ module.exports = async (params, user, app) => {
 	}
 
 	// Get 'includeMyRenotes' parameter
-	const [includeMyRenotes = true, includeMyRenotesErr] = $(params.includeMyRenotes).optional.boolean().get();
+	const [includeMyRenotes = true, includeMyRenotesErr] = $.bool.optional().get(params.includeMyRenotes);
 	if (includeMyRenotesErr) throw 'invalid includeMyRenotes param';
 
 	// Get 'includeRenotedMyNotes' parameter
-	const [includeRenotedMyNotes = true, includeRenotedMyNotesErr] = $(params.includeRenotedMyNotes).optional.boolean().get();
+	const [includeRenotedMyNotes = true, includeRenotedMyNotesErr] = $.bool.optional().get(params.includeRenotedMyNotes);
 	if (includeRenotedMyNotesErr) throw 'invalid includeRenotedMyNotes param';
 
 	const [followings, watchingChannelIds, mutedUserIds] = await Promise.all([
diff --git a/src/server/api/endpoints/notes/trend.ts b/src/server/api/endpoints/notes/trend.ts
index 915d45ce91..9cb3debe63 100644
--- a/src/server/api/endpoints/notes/trend.ts
+++ b/src/server/api/endpoints/notes/trend.ts
@@ -14,27 +14,27 @@ import Note, { pack } from '../../../../models/note';
  */
 module.exports = (params, user) => new Promise(async (res, rej) => {
 	// Get 'limit' parameter
-	const [limit = 10, limitErr] = $(params.limit).optional.number().range(1, 100).get();
+	const [limit = 10, limitErr] = $.num.optional().range(1, 100).get(params.limit);
 	if (limitErr) return rej('invalid limit param');
 
 	// Get 'offset' parameter
-	const [offset = 0, offsetErr] = $(params.offset).optional.number().min(0).get();
+	const [offset = 0, offsetErr] = $.num.optional().min(0).get(params.offset);
 	if (offsetErr) return rej('invalid offset param');
 
 	// Get 'reply' parameter
-	const [reply, replyErr] = $(params.reply).optional.boolean().get();
+	const [reply, replyErr] = $.bool.optional().get(params.reply);
 	if (replyErr) return rej('invalid reply param');
 
 	// Get 'renote' parameter
-	const [renote, renoteErr] = $(params.renote).optional.boolean().get();
+	const [renote, renoteErr] = $.bool.optional().get(params.renote);
 	if (renoteErr) return rej('invalid renote param');
 
 	// Get 'media' parameter
-	const [media, mediaErr] = $(params.media).optional.boolean().get();
+	const [media, mediaErr] = $.bool.optional().get(params.media);
 	if (mediaErr) return rej('invalid media param');
 
 	// Get 'poll' parameter
-	const [poll, pollErr] = $(params.poll).optional.boolean().get();
+	const [poll, pollErr] = $.bool.optional().get(params.poll);
 	if (pollErr) return rej('invalid poll param');
 
 	const query = {
diff --git a/src/server/api/endpoints/notes/user-list-timeline.ts b/src/server/api/endpoints/notes/user-list-timeline.ts
index 8d4eb590cb..9f8397d679 100644
--- a/src/server/api/endpoints/notes/user-list-timeline.ts
+++ b/src/server/api/endpoints/notes/user-list-timeline.ts
@@ -12,23 +12,23 @@ import UserList from '../../../../models/user-list';
  */
 module.exports = async (params, user, app) => {
 	// Get 'limit' parameter
-	const [limit = 10, limitErr] = $(params.limit).optional.number().range(1, 100).get();
+	const [limit = 10, limitErr] = $.num.optional().range(1, 100).get(params.limit);
 	if (limitErr) throw 'invalid limit param';
 
 	// Get 'sinceId' parameter
-	const [sinceId, sinceIdErr] = $(params.sinceId).optional.type(ID).get();
+	const [sinceId, sinceIdErr] = $.type(ID).optional().get(params.sinceId);
 	if (sinceIdErr) throw 'invalid sinceId param';
 
 	// Get 'untilId' parameter
-	const [untilId, untilIdErr] = $(params.untilId).optional.type(ID).get();
+	const [untilId, untilIdErr] = $.type(ID).optional().get(params.untilId);
 	if (untilIdErr) throw 'invalid untilId param';
 
 	// Get 'sinceDate' parameter
-	const [sinceDate, sinceDateErr] = $(params.sinceDate).optional.number().get();
+	const [sinceDate, sinceDateErr] = $.num.optional().get(params.sinceDate);
 	if (sinceDateErr) throw 'invalid sinceDate param';
 
 	// Get 'untilDate' parameter
-	const [untilDate, untilDateErr] = $(params.untilDate).optional.number().get();
+	const [untilDate, untilDateErr] = $.num.optional().get(params.untilDate);
 	if (untilDateErr) throw 'invalid untilDate param';
 
 	// Check if only one of sinceId, untilId, sinceDate, untilDate specified
@@ -37,15 +37,15 @@ module.exports = async (params, user, app) => {
 	}
 
 	// Get 'includeMyRenotes' parameter
-	const [includeMyRenotes = true, includeMyRenotesErr] = $(params.includeMyRenotes).optional.boolean().get();
+	const [includeMyRenotes = true, includeMyRenotesErr] = $.bool.optional().get(params.includeMyRenotes);
 	if (includeMyRenotesErr) throw 'invalid includeMyRenotes param';
 
 	// Get 'includeRenotedMyNotes' parameter
-	const [includeRenotedMyNotes = true, includeRenotedMyNotesErr] = $(params.includeRenotedMyNotes).optional.boolean().get();
+	const [includeRenotedMyNotes = true, includeRenotedMyNotesErr] = $.bool.optional().get(params.includeRenotedMyNotes);
 	if (includeRenotedMyNotesErr) throw 'invalid includeRenotedMyNotes param';
 
 	// Get 'listId' parameter
-	const [listId, listIdErr] = $(params.listId).type(ID).get();
+	const [listId, listIdErr] = $.type(ID).get(params.listId);
 	if (listIdErr) throw 'invalid listId param';
 
 	const [list, mutedUserIds] = await Promise.all([
diff --git a/src/server/api/endpoints/othello/games.ts b/src/server/api/endpoints/othello/games.ts
index 05bff180c1..2320a34b04 100644
--- a/src/server/api/endpoints/othello/games.ts
+++ b/src/server/api/endpoints/othello/games.ts
@@ -3,19 +3,19 @@ import OthelloGame, { pack } from '../../../../models/othello-game';
 
 module.exports = (params, user) => new Promise(async (res, rej) => {
 	// Get 'my' parameter
-	const [my = false, myErr] = $(params.my).optional.boolean().get();
+	const [my = false, myErr] = $.bool.optional().get(params.my);
 	if (myErr) return rej('invalid my param');
 
 	// Get 'limit' parameter
-	const [limit = 10, limitErr] = $(params.limit).optional.number().range(1, 100).get();
+	const [limit = 10, limitErr] = $.num.optional().range(1, 100).get(params.limit);
 	if (limitErr) return rej('invalid limit param');
 
 	// Get 'sinceId' parameter
-	const [sinceId, sinceIdErr] = $(params.sinceId).optional.type(ID).get();
+	const [sinceId, sinceIdErr] = $.type(ID).optional().get(params.sinceId);
 	if (sinceIdErr) return rej('invalid sinceId param');
 
 	// Get 'untilId' parameter
-	const [untilId, untilIdErr] = $(params.untilId).optional.type(ID).get();
+	const [untilId, untilIdErr] = $.type(ID).optional().get(params.untilId);
 	if (untilIdErr) return rej('invalid untilId param');
 
 	// Check if both of sinceId and untilId is specified
diff --git a/src/server/api/endpoints/othello/games/show.ts b/src/server/api/endpoints/othello/games/show.ts
index 991bb9622e..6b2f5ce137 100644
--- a/src/server/api/endpoints/othello/games/show.ts
+++ b/src/server/api/endpoints/othello/games/show.ts
@@ -4,7 +4,7 @@ import Othello from '../../../../../othello/core';
 
 module.exports = (params, user) => new Promise(async (res, rej) => {
 	// Get 'gameId' parameter
-	const [gameId, gameIdErr] = $(params.gameId).type(ID).get();
+	const [gameId, gameIdErr] = $.type(ID).get(params.gameId);
 	if (gameIdErr) return rej('invalid gameId param');
 
 	const game = await OthelloGame.findOne({ _id: gameId });
diff --git a/src/server/api/endpoints/othello/match.ts b/src/server/api/endpoints/othello/match.ts
index 9769c94da3..e70e579755 100644
--- a/src/server/api/endpoints/othello/match.ts
+++ b/src/server/api/endpoints/othello/match.ts
@@ -7,7 +7,7 @@ import { eighteight } from '../../../../othello/maps';
 
 module.exports = (params, user) => new Promise(async (res, rej) => {
 	// Get 'userId' parameter
-	const [childId, childIdErr] = $(params.userId).type(ID).get();
+	const [childId, childIdErr] = $.type(ID).get(params.userId);
 	if (childIdErr) return rej('invalid userId param');
 
 	// Myself
diff --git a/src/server/api/endpoints/sw/register.ts b/src/server/api/endpoints/sw/register.ts
index 222e6edc8e..b22a8b08ef 100644
--- a/src/server/api/endpoints/sw/register.ts
+++ b/src/server/api/endpoints/sw/register.ts
@@ -9,15 +9,15 @@ import Subscription from '../../../../models/sw-subscription';
  */
 module.exports = async (params, user, app) => new Promise(async (res, rej) => {
 	// Get 'endpoint' parameter
-	const [endpoint, endpointErr] = $(params.endpoint).string().get();
+	const [endpoint, endpointErr] = $.str.get(params.endpoint);
 	if (endpointErr) return rej('invalid endpoint param');
 
 	// Get 'auth' parameter
-	const [auth, authErr] = $(params.auth).string().get();
+	const [auth, authErr] = $.str.get(params.auth);
 	if (authErr) return rej('invalid auth param');
 
 	// Get 'publickey' parameter
-	const [publickey, publickeyErr] = $(params.publickey).string().get();
+	const [publickey, publickeyErr] = $.str.get(params.publickey);
 	if (publickeyErr) return rej('invalid publickey param');
 
 	// if already subscribed
diff --git a/src/server/api/endpoints/username/available.ts b/src/server/api/endpoints/username/available.ts
index 65b297683d..b11bec4e58 100644
--- a/src/server/api/endpoints/username/available.ts
+++ b/src/server/api/endpoints/username/available.ts
@@ -13,7 +13,7 @@ import { validateUsername } from '../../../../models/user';
  */
 module.exports = async (params) => new Promise(async (res, rej) => {
 	// Get 'username' parameter
-	const [username, usernameError] = $(params.username).string().pipe(validateUsername).get();
+	const [username, usernameError] = $.str.pipe(validateUsername).get(params.username);
 	if (usernameError) return rej('invalid username param');
 
 	// Get exist
diff --git a/src/server/api/endpoints/users.ts b/src/server/api/endpoints/users.ts
index 2f7d00fa84..eb581cb7e6 100644
--- a/src/server/api/endpoints/users.ts
+++ b/src/server/api/endpoints/users.ts
@@ -9,15 +9,15 @@ import User, { pack } from '../../../models/user';
  */
 module.exports = (params, me) => new Promise(async (res, rej) => {
 	// Get 'limit' parameter
-	const [limit = 10, limitErr] = $(params.limit).optional.number().range(1, 100).get();
+	const [limit = 10, limitErr] = $.num.optional().range(1, 100).get(params.limit);
 	if (limitErr) return rej('invalid limit param');
 
 	// Get 'offset' parameter
-	const [offset = 0, offsetErr] = $(params.offset).optional.number().min(0).get();
+	const [offset = 0, offsetErr] = $.num.optional().min(0).get(params.offset);
 	if (offsetErr) return rej('invalid offset param');
 
 	// Get 'sort' parameter
-	const [sort, sortError] = $(params.sort).optional.string().or('+follower|-follower').get();
+	const [sort, sortError] = $.str.optional().or('+follower|-follower').get(params.sort);
 	if (sortError) return rej('invalid sort param');
 
 	// Construct query
diff --git a/src/server/api/endpoints/users/followers.ts b/src/server/api/endpoints/users/followers.ts
index 7892f633d4..810cd7341b 100644
--- a/src/server/api/endpoints/users/followers.ts
+++ b/src/server/api/endpoints/users/followers.ts
@@ -12,19 +12,19 @@ import { getFriendIds } from '../../common/get-friends';
  */
 module.exports = (params, me) => new Promise(async (res, rej) => {
 	// Get 'userId' parameter
-	const [userId, userIdErr] = $(params.userId).type(ID).get();
+	const [userId, userIdErr] = $.type(ID).get(params.userId);
 	if (userIdErr) return rej('invalid userId param');
 
 	// Get 'iknow' parameter
-	const [iknow = false, iknowErr] = $(params.iknow).optional.boolean().get();
+	const [iknow = false, iknowErr] = $.bool.optional().get(params.iknow);
 	if (iknowErr) return rej('invalid iknow param');
 
 	// Get 'limit' parameter
-	const [limit = 10, limitErr] = $(params.limit).optional.number().range(1, 100).get();
+	const [limit = 10, limitErr] = $.num.optional().range(1, 100).get(params.limit);
 	if (limitErr) return rej('invalid limit param');
 
 	// Get 'cursor' parameter
-	const [cursor = null, cursorErr] = $(params.cursor).optional.type(ID).get();
+	const [cursor = null, cursorErr] = $.type(ID).optional().get(params.cursor);
 	if (cursorErr) return rej('invalid cursor param');
 
 	// Lookup user
diff --git a/src/server/api/endpoints/users/following.ts b/src/server/api/endpoints/users/following.ts
index e584e61f9c..3373b9d632 100644
--- a/src/server/api/endpoints/users/following.ts
+++ b/src/server/api/endpoints/users/following.ts
@@ -16,19 +16,19 @@ import { getFriendIds } from '../../common/get-friends';
  */
 module.exports = (params, me) => new Promise(async (res, rej) => {
 	// Get 'userId' parameter
-	const [userId, userIdErr] = $(params.userId).type(ID).get();
+	const [userId, userIdErr] = $.type(ID).get(params.userId);
 	if (userIdErr) return rej('invalid userId param');
 
 	// Get 'iknow' parameter
-	const [iknow = false, iknowErr] = $(params.iknow).optional.boolean().get();
+	const [iknow = false, iknowErr] = $.bool.optional().get(params.iknow);
 	if (iknowErr) return rej('invalid iknow param');
 
 	// Get 'limit' parameter
-	const [limit = 10, limitErr] = $(params.limit).optional.number().range(1, 100).get();
+	const [limit = 10, limitErr] = $.num.optional().range(1, 100).get(params.limit);
 	if (limitErr) return rej('invalid limit param');
 
 	// Get 'cursor' parameter
-	const [cursor = null, cursorErr] = $(params.cursor).optional.type(ID).get();
+	const [cursor = null, cursorErr] = $.type(ID).optional().get(params.cursor);
 	if (cursorErr) return rej('invalid cursor param');
 
 	// Lookup user
diff --git a/src/server/api/endpoints/users/get_frequently_replied_users.ts b/src/server/api/endpoints/users/get_frequently_replied_users.ts
index 034684260c..64d737a06b 100644
--- a/src/server/api/endpoints/users/get_frequently_replied_users.ts
+++ b/src/server/api/endpoints/users/get_frequently_replied_users.ts
@@ -7,11 +7,11 @@ import User, { pack } from '../../../../models/user';
 
 module.exports = (params, me) => new Promise(async (res, rej) => {
 	// Get 'userId' parameter
-	const [userId, userIdErr] = $(params.userId).type(ID).get();
+	const [userId, userIdErr] = $.type(ID).get(params.userId);
 	if (userIdErr) return rej('invalid userId param');
 
 	// Get 'limit' parameter
-	const [limit = 10, limitErr] = $(params.limit).optional.number().range(1, 100).get();
+	const [limit = 10, limitErr] = $.num.optional().range(1, 100).get(params.limit);
 	if (limitErr) return rej('invalid limit param');
 
 	// Lookup user
diff --git a/src/server/api/endpoints/users/lists/create.ts b/src/server/api/endpoints/users/lists/create.ts
index 79a680c736..100a78b872 100644
--- a/src/server/api/endpoints/users/lists/create.ts
+++ b/src/server/api/endpoints/users/lists/create.ts
@@ -9,7 +9,7 @@ import UserList, { pack } from '../../../../../models/user-list';
  */
 module.exports = async (params, user) => new Promise(async (res, rej) => {
 	// Get 'title' parameter
-	const [title, titleErr] = $(params.title).string().range(1, 100).get();
+	const [title, titleErr] = $.str.range(1, 100).get(params.title);
 	if (titleErr) return rej('invalid title param');
 
 	// insert
diff --git a/src/server/api/endpoints/users/lists/push.ts b/src/server/api/endpoints/users/lists/push.ts
index ceb5692c81..da5a9a134c 100644
--- a/src/server/api/endpoints/users/lists/push.ts
+++ b/src/server/api/endpoints/users/lists/push.ts
@@ -11,7 +11,7 @@ import { deliver } from '../../../../../queue';
  */
 module.exports = async (params, me) => new Promise(async (res, rej) => {
 	// Get 'listId' parameter
-	const [listId, listIdErr] = $(params.listId).type(ID).get();
+	const [listId, listIdErr] = $.type(ID).get(params.listId);
 	if (listIdErr) return rej('invalid listId param');
 
 	// Fetch the list
@@ -25,7 +25,7 @@ module.exports = async (params, me) => new Promise(async (res, rej) => {
 	}
 
 	// Get 'userId' parameter
-	const [userId, userIdErr] = $(params.userId).type(ID).get();
+	const [userId, userIdErr] = $.type(ID).get(params.userId);
 	if (userIdErr) return rej('invalid userId param');
 
 	// Fetch the user
diff --git a/src/server/api/endpoints/users/lists/show.ts b/src/server/api/endpoints/users/lists/show.ts
index 54e1df7b2f..16cb3382fd 100644
--- a/src/server/api/endpoints/users/lists/show.ts
+++ b/src/server/api/endpoints/users/lists/show.ts
@@ -6,7 +6,7 @@ import UserList, { pack } from '../../../../../models/user-list';
  */
 module.exports = async (params, me) => new Promise(async (res, rej) => {
 	// Get 'listId' parameter
-	const [listId, listIdErr] = $(params.listId).type(ID).get();
+	const [listId, listIdErr] = $.type(ID).get(params.listId);
 	if (listIdErr) return rej('invalid listId param');
 
 	// Fetch the list
diff --git a/src/server/api/endpoints/users/notes.ts b/src/server/api/endpoints/users/notes.ts
index 67b14b36a3..061c363d0f 100644
--- a/src/server/api/endpoints/users/notes.ts
+++ b/src/server/api/endpoints/users/notes.ts
@@ -11,11 +11,11 @@ import User from '../../../../models/user';
  */
 module.exports = (params, me) => new Promise(async (res, rej) => {
 	// Get 'userId' parameter
-	const [userId, userIdErr] = $(params.userId).optional.type(ID).get();
+	const [userId, userIdErr] = $.type(ID).optional().get(params.userId);
 	if (userIdErr) return rej('invalid userId param');
 
 	// Get 'username' parameter
-	const [username, usernameErr] = $(params.username).optional.string().get();
+	const [username, usernameErr] = $.str.optional().get(params.username);
 	if (usernameErr) return rej('invalid username param');
 
 	if (userId === undefined && username === undefined) {
@@ -23,7 +23,7 @@ module.exports = (params, me) => new Promise(async (res, rej) => {
 	}
 
 	// Get 'host' parameter
-	const [host, hostErr] = $(params.host).optional.string().get();
+	const [host, hostErr] = $.str.optional().get(params.host);
 	if (hostErr) return rej('invalid host param');
 
 	if (userId === undefined && host === undefined) {
@@ -31,31 +31,31 @@ module.exports = (params, me) => new Promise(async (res, rej) => {
 	}
 
 	// Get 'includeReplies' parameter
-	const [includeReplies = true, includeRepliesErr] = $(params.includeReplies).optional.boolean().get();
+	const [includeReplies = true, includeRepliesErr] = $.bool.optional().get(params.includeReplies);
 	if (includeRepliesErr) return rej('invalid includeReplies param');
 
 	// Get 'withMedia' parameter
-	const [withMedia = false, withMediaErr] = $(params.withMedia).optional.boolean().get();
+	const [withMedia = false, withMediaErr] = $.bool.optional().get(params.withMedia);
 	if (withMediaErr) return rej('invalid withMedia param');
 
 	// Get 'limit' parameter
-	const [limit = 10, limitErr] = $(params.limit).optional.number().range(1, 100).get();
+	const [limit = 10, limitErr] = $.num.optional().range(1, 100).get(params.limit);
 	if (limitErr) return rej('invalid limit param');
 
 	// Get 'sinceId' parameter
-	const [sinceId, sinceIdErr] = $(params.sinceId).optional.type(ID).get();
+	const [sinceId, sinceIdErr] = $.type(ID).optional().get(params.sinceId);
 	if (sinceIdErr) return rej('invalid sinceId param');
 
 	// Get 'untilId' parameter
-	const [untilId, untilIdErr] = $(params.untilId).optional.type(ID).get();
+	const [untilId, untilIdErr] = $.type(ID).optional().get(params.untilId);
 	if (untilIdErr) return rej('invalid untilId param');
 
 	// Get 'sinceDate' parameter
-	const [sinceDate, sinceDateErr] = $(params.sinceDate).optional.number().get();
+	const [sinceDate, sinceDateErr] = $.num.optional().get(params.sinceDate);
 	if (sinceDateErr) throw 'invalid sinceDate param';
 
 	// Get 'untilDate' parameter
-	const [untilDate, untilDateErr] = $(params.untilDate).optional.number().get();
+	const [untilDate, untilDateErr] = $.num.optional().get(params.untilDate);
 	if (untilDateErr) throw 'invalid untilDate param';
 
 	// Check if only one of sinceId, untilId, sinceDate, untilDate specified
diff --git a/src/server/api/endpoints/users/recommendation.ts b/src/server/api/endpoints/users/recommendation.ts
index f48ac7cb28..620ae17ca2 100644
--- a/src/server/api/endpoints/users/recommendation.ts
+++ b/src/server/api/endpoints/users/recommendation.ts
@@ -16,11 +16,11 @@ import Mute from '../../../../models/mute';
  */
 module.exports = (params, me) => new Promise(async (res, rej) => {
 	// Get 'limit' parameter
-	const [limit = 10, limitErr] = $(params.limit).optional.number().range(1, 100).get();
+	const [limit = 10, limitErr] = $.num.optional().range(1, 100).get(params.limit);
 	if (limitErr) return rej('invalid limit param');
 
 	// Get 'offset' parameter
-	const [offset = 0, offsetErr] = $(params.offset).optional.number().min(0).get();
+	const [offset = 0, offsetErr] = $.num.optional().min(0).get(params.offset);
 	if (offsetErr) return rej('invalid offset param');
 
 	// ID list of the user itself and other users who the user follows
diff --git a/src/server/api/endpoints/users/search.ts b/src/server/api/endpoints/users/search.ts
index 48630c6fd3..cfbdc337bf 100644
--- a/src/server/api/endpoints/users/search.ts
+++ b/src/server/api/endpoints/users/search.ts
@@ -16,15 +16,15 @@ const escapeRegexp = require('escape-regexp');
  */
 module.exports = (params, me) => new Promise(async (res, rej) => {
 	// Get 'query' parameter
-	const [query, queryError] = $(params.query).string().pipe(x => x != '').get();
+	const [query, queryError] = $.str.pipe(x => x != '').get(params.query);
 	if (queryError) return rej('invalid query param');
 
 	// Get 'offset' parameter
-	const [offset = 0, offsetErr] = $(params.offset).optional.number().min(0).get();
+	const [offset = 0, offsetErr] = $.num.optional().min(0).get(params.offset);
 	if (offsetErr) return rej('invalid offset param');
 
 	// Get 'max' parameter
-	const [max = 10, maxErr] = $(params.max).optional.number().range(1, 30).get();
+	const [max = 10, maxErr] = $.num.optional().range(1, 30).get(params.max);
 	if (maxErr) return rej('invalid max param');
 
 	// If Elasticsearch is available, search by $
diff --git a/src/server/api/endpoints/users/search_by_username.ts b/src/server/api/endpoints/users/search_by_username.ts
index da38347956..5927d00faf 100644
--- a/src/server/api/endpoints/users/search_by_username.ts
+++ b/src/server/api/endpoints/users/search_by_username.ts
@@ -9,15 +9,15 @@ import User, { pack } from '../../../../models/user';
  */
 module.exports = (params, me) => new Promise(async (res, rej) => {
 	// Get 'query' parameter
-	const [query, queryError] = $(params.query).string().get();
+	const [query, queryError] = $.str.get(params.query);
 	if (queryError) return rej('invalid query param');
 
 	// Get 'offset' parameter
-	const [offset = 0, offsetErr] = $(params.offset).optional.number().min(0).get();
+	const [offset = 0, offsetErr] = $.num.optional().min(0).get(params.offset);
 	if (offsetErr) return rej('invalid offset param');
 
 	// Get 'limit' parameter
-	const [limit = 10, limitErr] = $(params.limit).optional.number().range(1, 100).get();
+	const [limit = 10, limitErr] = $.num.optional().range(1, 100).get(params.limit);
 	if (limitErr) return rej('invalid limit param');
 
 	const users = await User
diff --git a/src/server/api/endpoints/users/show.ts b/src/server/api/endpoints/users/show.ts
index 89a8684538..b8c6ff25c4 100644
--- a/src/server/api/endpoints/users/show.ts
+++ b/src/server/api/endpoints/users/show.ts
@@ -14,19 +14,19 @@ module.exports = (params, me) => new Promise(async (res, rej) => {
 	let user;
 
 	// Get 'userId' parameter
-	const [userId, userIdErr] = $(params.userId).optional.type(ID).get();
+	const [userId, userIdErr] = $.type(ID).optional().get(params.userId);
 	if (userIdErr) return rej('invalid userId param');
 
 	// Get 'userIds' parameter
-	const [userIds, userIdsErr] = $(params.userIds).optional.array($().type(ID)).get();
+	const [userIds, userIdsErr] = $.arr($.type(ID)).optional().get(params.userIds);
 	if (userIdsErr) return rej('invalid userIds param');
 
 	// Get 'username' parameter
-	const [username, usernameErr] = $(params.username).optional.string().get();
+	const [username, usernameErr] = $.str.optional().get(params.username);
 	if (usernameErr) return rej('invalid username param');
 
 	// Get 'host' parameter
-	const [host, hostErr] = $(params.host).nullable.optional.string().get();
+	const [host, hostErr] = $.str.optional().nullable().get(params.host);
 	if (hostErr) return rej('invalid host param');
 
 	if (userIds) {