refactor(frontend): Formまわりの型強化 (#16260)

* refactor(frontend): Formまわりの型強化

* fix

* avoid non-null assertion and add null check for safety

* refactor

* avoid non-null assertion and add null check for safety

* Update clip.vue

---------

Co-authored-by: syuilo <4439005+syuilo@users.noreply.github.com>

45 files changed, 344 insertions, 239 deletions

diff --git a/packages/frontend/src/os.ts b/packages/frontend/src/os.ts
index 83ad0ebdf9..bf0e5e1b37 100644
--- a/packages/frontend/src/os.ts
+++ b/packages/frontend/src/os.ts
@@ -13,7 +13,7 @@ import type { ComponentProps as CP } from 'vue-component-type-helpers';
 import type { Form, GetFormResultType } from '@/utility/form.js';
 import type { MenuItem } from '@/types/menu.js';
 import type { PostFormProps } from '@/types/post-form.js';
-import type { UploaderDialogFeatures } from '@/components/MkUploaderDialog.vue';
+import type { UploaderFeatures } from '@/composables/use-uploader.js';
 import type MkRoleSelectDialog_TypeReferenceOnly from '@/components/MkRoleSelectDialog.vue';
 import type MkEmojiPickerDialog_TypeReferenceOnly from '@/components/MkEmojiPickerDialog.vue';
 import { misskeyApi } from '@/utility/misskey-api.js';
@@ -837,7 +837,7 @@ export function launchUploader(
 	options?: {
 		folderId?: string | null;
 		multiple?: boolean;
-		features?: UploaderDialogFeatures;
+		features?: UploaderFeatures;
 	},
 ): Promise<Misskey.entities.DriveFile[]> {
 	return new Promise(async (res, rej) => {
diff --git a/packages/frontend/src/pages/clip.vue b/packages/frontend/src/pages/clip.vue
index 8843812544..8176fb519b 100644
--- a/packages/frontend/src/pages/clip.vue
+++ b/packages/frontend/src/pages/clip.vue
@@ -76,7 +76,8 @@ watch(() => props.clipId, async () => {
 	clip.value = await misskeyApi('clips/show', {
 		clipId: props.clipId,
 	});
-	favorited.value = clip.value.isFavorited;
+
+	favorited.value = clip.value!.isFavorited ?? false;
 }, {
 	immediate: true,
 });
@@ -108,6 +109,8 @@ const headerActions = computed(() => clip.value && isOwned.value ? [{
 	icon: 'ti ti-pencil',
 	text: i18n.ts.edit,
 	handler: async (): Promise<void> => {
+		if (clip.value == null) return;
+
 		const { canceled, result } = await os.form(clip.value.name, {
 			name: {
 				type: 'string',
@@ -128,6 +131,7 @@ const headerActions = computed(() => clip.value && isOwned.value ? [{
 				default: clip.value.isPublic,
 			},
 		});
+
 		if (canceled) return;
 
 		os.apiWithDialog('clips/update', {
@@ -178,6 +182,8 @@ const headerActions = computed(() => clip.value && isOwned.value ? [{
 	text: i18n.ts.delete,
 	danger: true,
 	handler: async (): Promise<void> => {
+		if (clip.value == null) return;
+
 		const { canceled } = await os.confirm({
 			type: 'warning',
 			text: i18n.tsx.deleteAreYouSure({ x: clip.value.name }),
diff --git a/packages/frontend/src/pages/my-clips/index.vue b/packages/frontend/src/pages/my-clips/index.vue
index 4c664a0951..f48dc5be4d 100644
--- a/packages/frontend/src/pages/my-clips/index.vue
+++ b/packages/frontend/src/pages/my-clips/index.vue
@@ -64,6 +64,7 @@ async function create() {
 			default: false,
 		},
 	});
+
 	if (canceled) return;
 
 	os.apiWithDialog('clips/create', result);
diff --git a/packages/frontend/src/pages/registry.keys.vue b/packages/frontend/src/pages/registry.keys.vue
index 39575fe1f7..8eb2ab9fd0 100644
--- a/packages/frontend/src/pages/registry.keys.vue
+++ b/packages/frontend/src/pages/registry.keys.vue
@@ -79,7 +79,9 @@ async function createKey() {
 			default: scope.value.join('/'),
 		},
 	});
+
 	if (canceled) return;
+
 	os.apiWithDialog('i/registry/set', {
 		scope: result.scope.split('/'),
 		key: result.key,
diff --git a/packages/frontend/src/pages/registry.vue b/packages/frontend/src/pages/registry.vue
index 5e59082b50..3762dadd12 100644
--- a/packages/frontend/src/pages/registry.vue
+++ b/packages/frontend/src/pages/registry.vue
@@ -56,7 +56,9 @@ async function createKey() {
 			label: i18n.ts._registry.scope,
 		},
 	});
+
 	if (canceled) return;
+
 	os.apiWithDialog('i/registry/set', {
 		scope: result.scope.split('/'),
 		key: result.key,
diff --git a/packages/frontend/src/plugin.ts b/packages/frontend/src/plugin.ts
index 6010180e68..d6007a27ed 100644
--- a/packages/frontend/src/plugin.ts
+++ b/packages/frontend/src/plugin.ts
@@ -14,12 +14,13 @@ import * as os from '@/os.js';
 import { misskeyApi } from '@/utility/misskey-api.js';
 import { i18n } from '@/i18n.js';
 import { prefer } from '@/preferences.js';
+import type { FormWithDefault } from '@/utility/form.js';
 
 export type Plugin = {
 	installId: string;
 	name: string;
 	active: boolean;
-	config?: Record<string, { default: any }>;
+	config?: FormWithDefault;
 	configData: Record<string, any>;
 	src: string | null;
 	version: string;
@@ -240,7 +241,7 @@ async function launchPlugin(id: Plugin['installId']): Promise<void> {
 	pluginLogs.value.set(plugin.installId, []);
 
 	function systemLog(message: string, isError = false): void {
-		pluginLogs.value.get(plugin.installId)?.push({
+		pluginLogs.value.get(plugin!.installId)?.push({
 			at: Date.now(),
 			isSystem: true,
 			message,
diff --git a/packages/frontend/src/store.ts b/packages/frontend/src/store.ts
index 9afaf2c9b9..e9402cfb70 100644
--- a/packages/frontend/src/store.ts
+++ b/packages/frontend/src/store.ts
@@ -29,7 +29,7 @@ export const store = markRaw(new Pizzax('base', {
 	},
 	memo: {
 		where: 'account',
-		default: null,
+		default: null as string | null,
 	},
 	reactionAcceptance: {
 		where: 'account',
diff --git a/packages/frontend/src/ui/deck/tl-note-notification.ts b/packages/frontend/src/ui/deck/tl-note-notification.ts
index 728c0d0d29..e9b14e70ee 100644
--- a/packages/frontend/src/ui/deck/tl-note-notification.ts
+++ b/packages/frontend/src/ui/deck/tl-note-notification.ts
@@ -29,7 +29,8 @@ export async function soundSettingsButton(soundSetting: Ref<SoundStore>): Promis
 			label: i18n.ts.sound,
 			default: soundSetting.value.type ?? 'none',
 			enum: soundsTypes.map(f => ({
-				value: f ?? 'none', label: getSoundTypeName(f),
+				value: f ?? 'none' as Exclude<SoundType, null> | 'none',
+				label: getSoundTypeName(f),
 			})),
 		},
 		soundFile: {
@@ -81,16 +82,17 @@ export async function soundSettingsButton(soundSetting: Ref<SoundStore>): Promis
 			},
 		},
 	});
+
 	if (canceled) return;
 
 	const res = buildSoundStore(result);
 	if (res) soundSetting.value = res;
 
-	function buildSoundStore(result: any): SoundStore | null {
-		const type = (result.type === 'none' ? null : result.type) as SoundType;
-		const volume = result.volume as number;
-		const fileId = result.soundFile?.id ?? (soundSetting.value.type === '_driveFile_' ? soundSetting.value.fileId : undefined);
-		const fileUrl = result.soundFile?.url ?? (soundSetting.value.type === '_driveFile_' ? soundSetting.value.fileUrl : undefined);
+	function buildSoundStore(r: NonNullable<typeof result>): SoundStore | null {
+		const type = (r.type === 'none' ? null : r.type);
+		const volume = r.volume;
+		const fileId = r.soundFile?.id ?? (soundSetting.value.type === '_driveFile_' ? soundSetting.value.fileId : undefined);
+		const fileUrl = r.soundFile?.url ?? (soundSetting.value.type === '_driveFile_' ? soundSetting.value.fileUrl : undefined);
 
 		if (type === '_driveFile_') {
 			if (!fileUrl || !fileId) {
diff --git a/packages/frontend/src/utility/form.ts b/packages/frontend/src/utility/form.ts
index 1032e97ac9..2b765dc714 100644
--- a/packages/frontend/src/utility/form.ts
+++ b/packages/frontend/src/utility/form.ts
@@ -5,55 +5,59 @@
 
 import * as Misskey from 'misskey-js';
 
-type EnumItem = string | {
+export type EnumItem = string | {
 	label: string;
-	value: string;
+	value: unknown;
 };
 
 type Hidden = boolean | ((v: any) => boolean);
 
-export type FormItem = {
+interface FormItemBase {
 	label?: string;
+	hidden?: Hidden;
+}
+
+export interface StringFormItem extends FormItemBase {
 	type: 'string';
 	default?: string | null;
 	description?: string;
 	required?: boolean;
-	hidden?: Hidden;
 	multiline?: boolean;
 	treatAsMfm?: boolean;
-} | {
-	label?: string;
+}
+
+export interface NumberFormItem extends FormItemBase {
 	type: 'number';
 	default?: number | null;
 	description?: string;
 	required?: boolean;
-	hidden?: Hidden;
 	step?: number;
-} | {
-	label?: string;
+}
+
+export interface BooleanFormItem extends FormItemBase {
 	type: 'boolean';
 	default?: boolean | null;
 	description?: string;
-	hidden?: Hidden;
-} | {
-	label?: string;
+}
+
+export interface EnumFormItem extends FormItemBase {
 	type: 'enum';
 	default?: string | null;
 	required?: boolean;
-	hidden?: Hidden;
 	enum: EnumItem[];
-} | {
-	label?: string;
+}
+
+export interface RadioFormItem extends FormItemBase {
 	type: 'radio';
 	default?: unknown | null;
 	required?: boolean;
-	hidden?: Hidden;
 	options: {
 		label: string;
 		value: unknown;
 	}[];
-} | {
-	label?: string;
+}
+
+export interface RangeFormItem extends FormItemBase {
 	type: 'range';
 	default?: number | null;
 	description?: string;
@@ -62,42 +66,80 @@ export type FormItem = {
 	min: number;
 	max: number;
 	textConverter?: (value: number) => string;
-	hidden?: Hidden;
-} | {
-	label?: string;
+}
+
+export interface ObjectFormItem extends FormItemBase {
 	type: 'object';
 	default?: Record<string, unknown> | null;
-	hidden: Hidden;
-} | {
-	label?: string;
+}
+
+export interface ArrayFormItem extends FormItemBase {
 	type: 'array';
 	default?: unknown[] | null;
-	hidden: Hidden;
-} | {
+}
+
+export interface ButtonFormItem extends FormItemBase {
 	type: 'button';
 	content?: string;
-	hidden?: Hidden;
 	action: (ev: MouseEvent, v: any) => void;
-} | {
+}
+
+export interface DriveFileFormItem extends FormItemBase {
 	type: 'drive-file';
 	defaultFileId?: string | null;
-	hidden?: Hidden;
 	validate?: (v: Misskey.entities.DriveFile) => Promise<boolean>;
-};
+}
+
+export type FormItem =
+	StringFormItem |
+	NumberFormItem |
+	BooleanFormItem |
+	EnumFormItem |
+	RadioFormItem |
+	RangeFormItem |
+	ObjectFormItem |
+	ArrayFormItem |
+	ButtonFormItem |
+	DriveFileFormItem;
 
 export type Form = Record<string, FormItem>;
 
+export type FormItemWithDefault = FormItem & {
+	default: unknown;
+};
+
+export type FormWithDefault = Record<string, FormItemWithDefault>;
+
+type GetRadioItemType<Item extends RadioFormItem = RadioFormItem> = Item['options'][number]['value'];
+type GetEnumItemType<Item extends EnumFormItem, E = Item['enum'][number]> = E extends { value: unknown } ? E['value'] : E;
+
+type InferDefault<T, Fallback> = T extends { default: infer D }
+	? D extends undefined ? Fallback : D
+	: Fallback;
+
+type NonNullableIfRequired<T, Item extends FormItem> =
+	Item extends { required: false } ? T | null | undefined : NonNullable<T>;
+
 type GetItemType<Item extends FormItem> =
-	Item['type'] extends 'string' ? string :
-	Item['type'] extends 'number' ? number :
-	Item['type'] extends 'boolean' ? boolean :
-	Item['type'] extends 'radio' ? unknown :
-	Item['type'] extends 'range' ? number :
-	Item['type'] extends 'enum' ? string :
-	Item['type'] extends 'array' ? unknown[] :
-	Item['type'] extends 'object' ? Record<string, unknown> :
-	Item['type'] extends 'drive-file' ? Misskey.entities.DriveFile | undefined :
-	never;
+	Item extends StringFormItem
+		? NonNullableIfRequired<InferDefault<Item, string>, Item>
+	: Item extends NumberFormItem
+		? NonNullableIfRequired<InferDefault<Item, number>, Item>
+	: Item extends BooleanFormItem
+		? boolean
+	: Item extends RadioFormItem
+		? GetRadioItemType<Item>
+	: Item extends RangeFormItem
+		? NonNullableIfRequired<InferDefault<RangeFormItem, number>, Item>
+	: Item extends EnumFormItem
+		? GetEnumItemType<Item>
+	: Item extends ArrayFormItem
+		? NonNullableIfRequired<InferDefault<ArrayFormItem, unknown[]>, Item>
+	: Item extends ObjectFormItem
+		? NonNullableIfRequired<InferDefault<Item, Record<string, unknown>>, Item>
+	: Item extends DriveFileFormItem
+		? Misskey.entities.DriveFile | undefined
+	: never;
 
 export type GetFormResultType<F extends Form> = {
 	[P in keyof F]: GetItemType<F[P]>;
diff --git a/packages/frontend/src/utility/get-note-menu.ts b/packages/frontend/src/utility/get-note-menu.ts
index ea93444f08..5361c1252d 100644
--- a/packages/frontend/src/utility/get-note-menu.ts
+++ b/packages/frontend/src/utility/get-note-menu.ts
@@ -101,7 +101,7 @@ export async function getNoteClipMenu(props: {
 			const { canceled, result } = await os.form(i18n.ts.createNewClip, {
 				name: {
 					type: 'string',
-					default: null,
+					default: null as string | null,
 					label: i18n.ts.name,
 				},
 				description: {
diff --git a/packages/frontend/src/utility/get-user-menu.ts b/packages/frontend/src/utility/get-user-menu.ts
index 5c08b8c462..ad0864019b 100644
--- a/packages/frontend/src/utility/get-user-menu.ts
+++ b/packages/frontend/src/utility/get-user-menu.ts
@@ -132,6 +132,7 @@ export function getUserMenu(user: Misskey.entities.UserDetailed, router: Router
 		const userDetailed = await misskeyApi('users/show', {
 			userId: user.id,
 		});
+
 		const { canceled, result } = await os.form(i18n.ts.editMemo, {
 			memo: {
 				type: 'string',
@@ -141,6 +142,7 @@ export function getUserMenu(user: Misskey.entities.UserDetailed, router: Router
 				default: userDetailed.memo,
 			},
 		});
+
 		if (canceled) return;
 
 		os.apiWithDialog('users/update-memo', {
diff --git a/packages/frontend/src/widgets/WidgetActivity.vue b/packages/frontend/src/widgets/WidgetActivity.vue
index db03d1406c..9625abb4d1 100644
--- a/packages/frontend/src/widgets/WidgetActivity.vue
+++ b/packages/frontend/src/widgets/WidgetActivity.vue
@@ -25,29 +25,31 @@ import { useWidgetPropsManager } from './widget.js';
 import type { WidgetComponentProps, WidgetComponentEmits, WidgetComponentExpose } from './widget.js';
 import XCalendar from './WidgetActivity.calendar.vue';
 import XChart from './WidgetActivity.chart.vue';
-import type { GetFormResultType } from '@/utility/form.js';
+import type { FormWithDefault, GetFormResultType } from '@/utility/form.js';
 import { misskeyApiGet } from '@/utility/misskey-api.js';
 import MkContainer from '@/components/MkContainer.vue';
-import { $i } from '@/i.js';
+import { ensureSignin } from '@/i.js';
 import { i18n } from '@/i18n.js';
 
+const $i = ensureSignin();
+
 const name = 'activity';
 
 const widgetPropsDef = {
 	showHeader: {
-		type: 'boolean' as const,
+		type: 'boolean',
 		default: true,
 	},
 	transparent: {
-		type: 'boolean' as const,
+		type: 'boolean',
 		default: false,
 	},
 	view: {
-		type: 'number' as const,
+		type: 'number',
 		default: 0,
 		hidden: true,
 	},
-};
+} satisfies FormWithDefault;
 
 type WidgetProps = GetFormResultType<typeof widgetPropsDef>;
 
diff --git a/packages/frontend/src/widgets/WidgetAichan.vue b/packages/frontend/src/widgets/WidgetAichan.vue
index 2bc7facc88..3951de1d84 100644
--- a/packages/frontend/src/widgets/WidgetAichan.vue
+++ b/packages/frontend/src/widgets/WidgetAichan.vue
@@ -13,16 +13,16 @@ SPDX-License-Identifier: AGPL-3.0-only
 import { onMounted, onUnmounted, useTemplateRef } from 'vue';
 import { useWidgetPropsManager } from './widget.js';
 import type { WidgetComponentProps, WidgetComponentEmits, WidgetComponentExpose } from './widget.js';
-import type { GetFormResultType } from '@/utility/form.js';
+import type { FormWithDefault, GetFormResultType } from '@/utility/form.js';
 
 const name = 'ai';
 
 const widgetPropsDef = {
 	transparent: {
-		type: 'boolean' as const,
+		type: 'boolean',
 		default: false,
 	},
-};
+} satisfies FormWithDefault;
 
 type WidgetProps = GetFormResultType<typeof widgetPropsDef>;
 
@@ -42,6 +42,8 @@ const touched = () => {
 };
 
 const onMousemove = (ev: MouseEvent) => {
+	if (!live2d.value || !live2d.value.contentWindow) return;
+
 	const iframeRect = live2d.value.getBoundingClientRect();
 	live2d.value.contentWindow.postMessage({
 		type: 'moveCursor',
diff --git a/packages/frontend/src/widgets/WidgetAiscript.vue b/packages/frontend/src/widgets/WidgetAiscript.vue
index da71dcad29..a2d964718e 100644
--- a/packages/frontend/src/widgets/WidgetAiscript.vue
+++ b/packages/frontend/src/widgets/WidgetAiscript.vue
@@ -23,7 +23,7 @@ import { ref } from 'vue';
 import { Interpreter, Parser, utils } from '@syuilo/aiscript';
 import { useWidgetPropsManager } from './widget.js';
 import type { WidgetComponentEmits, WidgetComponentExpose, WidgetComponentProps } from './widget.js';
-import type { GetFormResultType } from '@/utility/form.js';
+import type { FormWithDefault, GetFormResultType } from '@/utility/form.js';
 import * as os from '@/os.js';
 import MkContainer from '@/components/MkContainer.vue';
 import { aiScriptReadline, createAiScriptEnv } from '@/aiscript/api.js';
@@ -35,16 +35,16 @@ const name = 'aiscript';
 
 const widgetPropsDef = {
 	showHeader: {
-		type: 'boolean' as const,
+		type: 'boolean',
 		default: true,
 	},
 	script: {
-		type: 'string' as const,
+		type: 'string',
 		multiline: true,
 		default: '(1 + 1)',
 		hidden: true,
 	},
-};
+} satisfies FormWithDefault;
 
 type WidgetProps = GetFormResultType<typeof widgetPropsDef>;
 
@@ -106,7 +106,7 @@ const run = async () => {
 	} catch (err) {
 		os.alert({
 			type: 'error',
-			text: err,
+			text: err instanceof Error ? err.message : String(err),
 		});
 	}
 };
diff --git a/packages/frontend/src/widgets/WidgetAiscriptApp.vue b/packages/frontend/src/widgets/WidgetAiscriptApp.vue
index 429b0e0ffb..fdd4eaae06 100644
--- a/packages/frontend/src/widgets/WidgetAiscriptApp.vue
+++ b/packages/frontend/src/widgets/WidgetAiscriptApp.vue
@@ -18,7 +18,7 @@ import type { Ref } from 'vue';
 import { Interpreter, Parser } from '@syuilo/aiscript';
 import { useWidgetPropsManager } from './widget.js';
 import type { WidgetComponentEmits, WidgetComponentExpose, WidgetComponentProps } from './widget.js';
-import type { GetFormResultType } from '@/utility/form.js';
+import type { FormWithDefault, GetFormResultType } from '@/utility/form.js';
 import * as os from '@/os.js';
 import { aiScriptReadline, createAiScriptEnv } from '@/aiscript/api.js';
 import { $i } from '@/i.js';
@@ -31,15 +31,15 @@ const name = 'aiscriptApp';
 
 const widgetPropsDef = {
 	script: {
-		type: 'string' as const,
+		type: 'string',
 		multiline: true,
 		default: '',
 	},
 	showHeader: {
-		type: 'boolean' as const,
+		type: 'boolean',
 		default: true,
 	},
-};
+} satisfies FormWithDefault;
 
 type WidgetProps = GetFormResultType<typeof widgetPropsDef>;
 
@@ -92,7 +92,7 @@ async function run() {
 		os.alert({
 			type: 'error',
 			title: 'AiScript Error',
-			text: err.message,
+			text: err instanceof Error ? err.message : String(err),
 		});
 	}
 }
diff --git a/packages/frontend/src/widgets/WidgetBirthdayFollowings.vue b/packages/frontend/src/widgets/WidgetBirthdayFollowings.vue
index 4790f143cb..d1991cd70a 100644
--- a/packages/frontend/src/widgets/WidgetBirthdayFollowings.vue
+++ b/packages/frontend/src/widgets/WidgetBirthdayFollowings.vue
@@ -12,7 +12,7 @@ SPDX-License-Identifier: AGPL-3.0-only
 	<div :class="$style.bdayFRoot">
 		<MkLoading v-if="fetching"/>
 		<div v-else-if="users.length > 0" :class="$style.bdayFGrid">
-			<MkAvatar v-for="user in users" :key="user.id" :user="user.followee" link preview></MkAvatar>
+			<MkAvatar v-for="user in users" :key="user.id" :user="user.followee!" link preview></MkAvatar>
 		</div>
 		<div v-else :class="$style.bdayFFallback">
 			<MkResult type="empty"/>
@@ -27,7 +27,7 @@ import * as Misskey from 'misskey-js';
 import { useInterval } from '@@/js/use-interval.js';
 import { useWidgetPropsManager } from './widget.js';
 import type { WidgetComponentEmits, WidgetComponentExpose, WidgetComponentProps } from './widget.js';
-import type { GetFormResultType } from '@/utility/form.js';
+import type { FormWithDefault, GetFormResultType } from '@/utility/form.js';
 import MkContainer from '@/components/MkContainer.vue';
 import { misskeyApi } from '@/utility/misskey-api.js';
 import { i18n } from '@/i18n.js';
@@ -37,10 +37,10 @@ const name = i18n.ts._widgets.birthdayFollowings;
 
 const widgetPropsDef = {
 	showHeader: {
-		type: 'boolean' as const,
+		type: 'boolean',
 		default: true,
 	},
-};
+} satisfies FormWithDefault;
 
 type WidgetProps = GetFormResultType<typeof widgetPropsDef>;
 
diff --git a/packages/frontend/src/widgets/WidgetButton.vue b/packages/frontend/src/widgets/WidgetButton.vue
index 4afe735a22..e88a960f87 100644
--- a/packages/frontend/src/widgets/WidgetButton.vue
+++ b/packages/frontend/src/widgets/WidgetButton.vue
@@ -15,7 +15,7 @@ SPDX-License-Identifier: AGPL-3.0-only
 import { Interpreter, Parser } from '@syuilo/aiscript';
 import { useWidgetPropsManager } from './widget.js';
 import type { WidgetComponentEmits, WidgetComponentExpose, WidgetComponentProps } from './widget.js';
-import type { GetFormResultType } from '@/utility/form.js';
+import type { FormWithDefault, GetFormResultType } from '@/utility/form.js';
 import * as os from '@/os.js';
 import { aiScriptReadline, createAiScriptEnv } from '@/aiscript/api.js';
 import { $i } from '@/i.js';
@@ -25,19 +25,19 @@ const name = 'button';
 
 const widgetPropsDef = {
 	label: {
-		type: 'string' as const,
+		type: 'string',
 		default: 'BUTTON',
 	},
 	colored: {
-		type: 'boolean' as const,
+		type: 'boolean',
 		default: true,
 	},
 	script: {
-		type: 'string' as const,
+		type: 'string',
 		multiline: true,
 		default: 'Mk:dialog("hello" "world")',
 	},
-};
+} satisfies FormWithDefault;
 
 type WidgetProps = GetFormResultType<typeof widgetPropsDef>;
 
@@ -81,7 +81,7 @@ const run = async () => {
 	} catch (err) {
 		os.alert({
 			type: 'error',
-			text: err,
+			text: err instanceof Error ? err.message : String(err),
 		});
 	}
 };
diff --git a/packages/frontend/src/widgets/WidgetCalendar.vue b/packages/frontend/src/widgets/WidgetCalendar.vue
index 54f78469b2..12c0a66c5c 100644
--- a/packages/frontend/src/widgets/WidgetCalendar.vue
+++ b/packages/frontend/src/widgets/WidgetCalendar.vue
@@ -41,7 +41,7 @@ SPDX-License-Identifier: AGPL-3.0-only
 import { ref } from 'vue';
 import { useWidgetPropsManager } from './widget.js';
 import type { WidgetComponentEmits, WidgetComponentExpose, WidgetComponentProps } from './widget.js';
-import type { GetFormResultType } from '@/utility/form.js';
+import type { FormWithDefault, GetFormResultType } from '@/utility/form.js';
 import { i18n } from '@/i18n.js';
 import { useInterval } from '@@/js/use-interval.js';
 
@@ -49,10 +49,10 @@ const name = 'calendar';
 
 const widgetPropsDef = {
 	transparent: {
-		type: 'boolean' as const,
+		type: 'boolean',
 		default: false,
 	},
-};
+} satisfies FormWithDefault;
 
 type WidgetProps = GetFormResultType<typeof widgetPropsDef>;
 
diff --git a/packages/frontend/src/widgets/WidgetChat.vue b/packages/frontend/src/widgets/WidgetChat.vue
index 43b2a6e522..8fee7f00f6 100644
--- a/packages/frontend/src/widgets/WidgetChat.vue
+++ b/packages/frontend/src/widgets/WidgetChat.vue
@@ -19,7 +19,7 @@ SPDX-License-Identifier: AGPL-3.0-only
 import { } from 'vue';
 import { useWidgetPropsManager } from './widget.js';
 import type { WidgetComponentEmits, WidgetComponentExpose, WidgetComponentProps } from './widget.js';
-import type { GetFormResultType } from '@/utility/form.js';
+import type { FormWithDefault, GetFormResultType } from '@/utility/form.js';
 import MkContainer from '@/components/MkContainer.vue';
 import { i18n } from '@/i18n.js';
 import MkChatHistories from '@/components/MkChatHistories.vue';
@@ -28,10 +28,10 @@ const name = 'chat';
 
 const widgetPropsDef = {
 	showHeader: {
-		type: 'boolean' as const,
+		type: 'boolean',
 		default: true,
 	},
-};
+} satisfies FormWithDefault;
 
 type WidgetProps = GetFormResultType<typeof widgetPropsDef>;
 
diff --git a/packages/frontend/src/widgets/WidgetClicker.vue b/packages/frontend/src/widgets/WidgetClicker.vue
index 87ffd3d732..282a1a6d93 100644
--- a/packages/frontend/src/widgets/WidgetClicker.vue
+++ b/packages/frontend/src/widgets/WidgetClicker.vue
@@ -14,7 +14,7 @@ SPDX-License-Identifier: AGPL-3.0-only
 <script lang="ts" setup>
 import { useWidgetPropsManager } from './widget.js';
 import type { WidgetComponentEmits, WidgetComponentExpose, WidgetComponentProps } from './widget.js';
-import type { GetFormResultType } from '@/utility/form.js';
+import type { FormWithDefault, GetFormResultType } from '@/utility/form.js';
 import MkContainer from '@/components/MkContainer.vue';
 import MkClickerGame from '@/components/MkClickerGame.vue';
 
@@ -22,10 +22,10 @@ const name = 'clicker';
 
 const widgetPropsDef = {
 	showHeader: {
-		type: 'boolean' as const,
+		type: 'boolean',
 		default: false,
 	},
-};
+} satisfies FormWithDefault;
 
 type WidgetProps = GetFormResultType<typeof widgetPropsDef>;
 
diff --git a/packages/frontend/src/widgets/WidgetClock.vue b/packages/frontend/src/widgets/WidgetClock.vue
index 826ecf6e02..7aa69a39b5 100644
--- a/packages/frontend/src/widgets/WidgetClock.vue
+++ b/packages/frontend/src/widgets/WidgetClock.vue
@@ -32,7 +32,7 @@ SPDX-License-Identifier: AGPL-3.0-only
 import { computed } from 'vue';
 import { useWidgetPropsManager } from './widget.js';
 import type { WidgetComponentEmits, WidgetComponentExpose, WidgetComponentProps } from './widget.js';
-import type { GetFormResultType } from '@/utility/form.js';
+import type { FormWithDefault, GetFormResultType } from '@/utility/form.js';
 import MkContainer from '@/components/MkContainer.vue';
 import MkAnalogClock from '@/components/MkAnalogClock.vue';
 import MkDigitalClock from '@/components/MkDigitalClock.vue';
@@ -43,76 +43,92 @@ const name = 'clock';
 
 const widgetPropsDef = {
 	transparent: {
-		type: 'boolean' as const,
+		type: 'boolean',
 		default: false,
 	},
 	size: {
-		type: 'radio' as const,
+		type: 'radio',
 		default: 'medium',
 		options: [{
-			value: 'small', label: i18n.ts.small,
+			value: 'small' as const,
+			label: i18n.ts.small,
 		}, {
-			value: 'medium', label: i18n.ts.medium,
+			value: 'medium' as const,
+			label: i18n.ts.medium,
 		}, {
-			value: 'large', label: i18n.ts.large,
+			value: 'large' as const,
+			label: i18n.ts.large,
 		}],
 	},
 	thickness: {
-		type: 'radio' as const,
+		type: 'radio',
 		default: 0.2,
 		options: [{
-			value: 0.1, label: 'thin',
+			value: 0.1 as const,
+			label: 'thin',
 		}, {
-			value: 0.2, label: 'medium',
+			value: 0.2 as const,
+			label: 'medium',
 		}, {
-			value: 0.3, label: 'thick',
+			value: 0.3 as const,
+			label: 'thick',
 		}],
 	},
 	graduations: {
-		type: 'radio' as const,
+		type: 'radio',
 		default: 'numbers',
 		options: [{
-			value: 'none', label: 'None',
+			value: 'none' as const,
+			label: 'None',
 		}, {
-			value: 'dots', label: 'Dots',
+			value: 'dots' as const,
+			label: 'Dots',
 		}, {
-			value: 'numbers', label: 'Numbers',
+			value: 'numbers' as const,
+			label: 'Numbers',
 		}],
 	},
 	fadeGraduations: {
-		type: 'boolean' as const,
+		type: 'boolean',
 		default: true,
 	},
 	sAnimation: {
-		type: 'radio' as const,
+		type: 'radio',
 		default: 'elastic',
 		options: [{
-			value: 'none', label: 'None',
+			value: 'none' as const,
+			label: 'None',
 		}, {
-			value: 'elastic', label: 'Elastic',
+			value: 'elastic' as const,
+			label: 'Elastic',
 		}, {
-			value: 'easeOut', label: 'Ease out',
+			value: 'easeOut' as const,
+			label: 'Ease out',
 		}],
 	},
 	twentyFour: {
-		type: 'boolean' as const,
+		type: 'boolean',
 		default: false,
 	},
 	label: {
-		type: 'radio' as const,
+		type: 'radio',
 		default: 'none',
 		options: [{
-			value: 'none', label: 'None',
+			value: 'none' as const,
+			label: 'None',
 		}, {
-			value: 'time', label: 'Time',
+			value: 'time' as const,
+			label: 'Time',
 		}, {
-			value: 'tz', label: 'TZ',
+			value: 'tz' as const,
+			label: 'TZ',
 		}, {
-			value: 'timeAndTz', label: 'Time + TZ',
+			value: 'timeAndTz' as const,
+			label: 'Time + TZ',
 		}],
 	},
 	timezone: {
-		type: 'enum' as const,
+		type: 'enum',
 		default: null,
 		enum: [...timezones.map((tz) => ({
 			label: tz.name,
@@ -122,7 +138,7 @@ const widgetPropsDef = {
 			value: null,
 		}],
 	},
-};
+} satisfies FormWithDefault;
 
 type WidgetProps = GetFormResultType<typeof widgetPropsDef>;
 
diff --git a/packages/frontend/src/widgets/WidgetDigitalClock.vue b/packages/frontend/src/widgets/WidgetDigitalClock.vue
index d79ec79d4f..b8cbc6429c 100644
--- a/packages/frontend/src/widgets/WidgetDigitalClock.vue
+++ b/packages/frontend/src/widgets/WidgetDigitalClock.vue
@@ -17,7 +17,7 @@ SPDX-License-Identifier: AGPL-3.0-only
 import { computed } from 'vue';
 import { useWidgetPropsManager } from './widget.js';
 import type { WidgetComponentEmits, WidgetComponentExpose, WidgetComponentProps } from './widget.js';
-import type { GetFormResultType } from '@/utility/form.js';
+import type { FormWithDefault, GetFormResultType } from '@/utility/form.js';
 import { timezones } from '@/utility/timezones.js';
 import MkDigitalClock from '@/components/MkDigitalClock.vue';
 
@@ -25,24 +25,24 @@ const name = 'digitalClock';
 
 const widgetPropsDef = {
 	transparent: {
-		type: 'boolean' as const,
+		type: 'boolean',
 		default: false,
 	},
 	fontSize: {
-		type: 'number' as const,
+		type: 'number',
 		default: 1.5,
 		step: 0.1,
 	},
 	showMs: {
-		type: 'boolean' as const,
+		type: 'boolean',
 		default: true,
 	},
 	showLabel: {
-		type: 'boolean' as const,
+		type: 'boolean',
 		default: true,
 	},
 	timezone: {
-		type: 'enum' as const,
+		type: 'enum',
 		default: null,
 		enum: [...timezones.map((tz) => ({
 			label: tz.name,
@@ -52,7 +52,7 @@ const widgetPropsDef = {
 			value: null,
 		}],
 	},
-};
+} satisfies FormWithDefault;
 
 type WidgetProps = GetFormResultType<typeof widgetPropsDef>;
 
diff --git a/packages/frontend/src/widgets/WidgetFederation.vue b/packages/frontend/src/widgets/WidgetFederation.vue
index ca6f27bd09..3e880af03b 100644
--- a/packages/frontend/src/widgets/WidgetFederation.vue
+++ b/packages/frontend/src/widgets/WidgetFederation.vue
@@ -4,7 +4,7 @@ SPDX-License-Identifier: AGPL-3.0-only
 -->
 
 <template>
-<MkContainer :showHeader="widgetProps.showHeader" :foldable="foldable" :scrollable="scrollable" data-cy-mkw-federation class="mkw-federation">
+<MkContainer :showHeader="widgetProps.showHeader" data-cy-mkw-federation class="mkw-federation">
 	<template #icon><i class="ti ti-whirl"></i></template>
 	<template #header>{{ i18n.ts._widgets.federation }}</template>
 
@@ -30,7 +30,7 @@ import * as Misskey from 'misskey-js';
 import { useInterval } from '@@/js/use-interval.js';
 import { useWidgetPropsManager } from './widget.js';
 import type { WidgetComponentEmits, WidgetComponentExpose, WidgetComponentProps } from './widget.js';
-import type { GetFormResultType } from '@/utility/form.js';
+import type { FormWithDefault, GetFormResultType } from '@/utility/form.js';
 import MkContainer from '@/components/MkContainer.vue';
 import MkMiniChart from '@/components/MkMiniChart.vue';
 import { misskeyApi, misskeyApiGet } from '@/utility/misskey-api.js';
@@ -42,10 +42,10 @@ const name = 'federation';
 
 const widgetPropsDef = {
 	showHeader: {
-		type: 'boolean' as const,
+		type: 'boolean',
 		default: true,
 	},
-};
+} satisfies FormWithDefault;
 
 type WidgetProps = GetFormResultType<typeof widgetPropsDef>;
 
diff --git a/packages/frontend/src/widgets/WidgetInstanceCloud.vue b/packages/frontend/src/widgets/WidgetInstanceCloud.vue
index 0c9f98f9e3..8053dd43cf 100644
--- a/packages/frontend/src/widgets/WidgetInstanceCloud.vue
+++ b/packages/frontend/src/widgets/WidgetInstanceCloud.vue
@@ -23,7 +23,7 @@ import * as Misskey from 'misskey-js';
 import { useInterval } from '@@/js/use-interval.js';
 import { useWidgetPropsManager } from './widget.js';
 import type { WidgetComponentEmits, WidgetComponentExpose, WidgetComponentProps } from './widget.js';
-import type { GetFormResultType } from '@/utility/form.js';
+import type { FormWithDefault, GetFormResultType } from '@/utility/form.js';
 import MkContainer from '@/components/MkContainer.vue';
 import MkTagCloud from '@/components/MkTagCloud.vue';
 import * as os from '@/os.js';
@@ -34,10 +34,10 @@ const name = 'instanceCloud';
 
 const widgetPropsDef = {
 	transparent: {
-		type: 'boolean' as const,
+		type: 'boolean',
 		default: false,
 	},
-};
+} satisfies FormWithDefault;
 
 type WidgetProps = GetFormResultType<typeof widgetPropsDef>;
 
diff --git a/packages/frontend/src/widgets/WidgetInstanceInfo.vue b/packages/frontend/src/widgets/WidgetInstanceInfo.vue
index 8d721298d5..722e6fadb2 100644
--- a/packages/frontend/src/widgets/WidgetInstanceInfo.vue
+++ b/packages/frontend/src/widgets/WidgetInstanceInfo.vue
@@ -5,7 +5,7 @@ SPDX-License-Identifier: AGPL-3.0-only
 
 <template>
 <div class="_panel">
-	<div :class="$style.container" :style="{ backgroundImage: instance.bannerUrl ? `url(${ instance.bannerUrl })` : null }">
+	<div :class="$style.container" :style="{ backgroundImage: instance.bannerUrl ? `url(${ instance.bannerUrl })` : undefined }">
 		<div :class="$style.iconContainer">
 			<img :src="instance.iconUrl ?? instance.faviconUrl ?? '/favicon.ico'" alt="" :class="$style.icon"/>
 		</div>
@@ -22,14 +22,14 @@ SPDX-License-Identifier: AGPL-3.0-only
 <script lang="ts" setup>
 import { useWidgetPropsManager } from './widget.js';
 import type { WidgetComponentEmits, WidgetComponentExpose, WidgetComponentProps } from './widget.js';
-import type { GetFormResultType } from '@/utility/form.js';
+import type { FormWithDefault, GetFormResultType } from '@/utility/form.js';
 import { host } from '@@/js/config.js';
 import { instance } from '@/instance.js';
 
 const name = 'instanceInfo';
 
 const widgetPropsDef = {
-};
+} satisfies FormWithDefault;
 
 type WidgetProps = GetFormResultType<typeof widgetPropsDef>;
 
diff --git a/packages/frontend/src/widgets/WidgetJobQueue.vue b/packages/frontend/src/widgets/WidgetJobQueue.vue
index 84fd4669cd..fba7d82062 100644
--- a/packages/frontend/src/widgets/WidgetJobQueue.vue
+++ b/packages/frontend/src/widgets/WidgetJobQueue.vue
@@ -54,7 +54,7 @@ SPDX-License-Identifier: AGPL-3.0-only
 import { onUnmounted, reactive, ref } from 'vue';
 import { useWidgetPropsManager } from './widget.js';
 import type { WidgetComponentEmits, WidgetComponentExpose, WidgetComponentProps } from './widget.js';
-import type { GetFormResultType } from '@/utility/form.js';
+import type { FormWithDefault, GetFormResultType } from '@/utility/form.js';
 import { useStream } from '@/stream.js';
 import kmg from '@/filters/kmg.js';
 import * as sound from '@/utility/sound.js';
@@ -66,14 +66,14 @@ const name = 'jobQueue';
 
 const widgetPropsDef = {
 	transparent: {
-		type: 'boolean' as const,
+		type: 'boolean',
 		default: false,
 	},
 	sound: {
-		type: 'boolean' as const,
+		type: 'boolean',
 		default: false,
 	},
-};
+} satisfies FormWithDefault;
 
 type WidgetProps = GetFormResultType<typeof widgetPropsDef>;
 
diff --git a/packages/frontend/src/widgets/WidgetMemo.vue b/packages/frontend/src/widgets/WidgetMemo.vue
index 3df5c5bfd7..2beca8c43a 100644
--- a/packages/frontend/src/widgets/WidgetMemo.vue
+++ b/packages/frontend/src/widgets/WidgetMemo.vue
@@ -9,7 +9,7 @@ SPDX-License-Identifier: AGPL-3.0-only
 	<template #header>{{ i18n.ts._widgets.memo }}</template>
 
 	<div :class="$style.root">
-		<textarea v-model="text" :style="`height: ${widgetProps.height}px;`" :class="$style.textarea" :placeholder="i18n.ts.placeholder" @input="onChange"></textarea>
+		<textarea v-model="text" :style="`height: ${widgetProps.height}px;`" :class="$style.textarea" :placeholder="i18n.ts.memo" @input="onChange"></textarea>
 		<button :class="$style.save" :disabled="!changed" class="_buttonPrimary" @click="saveMemo">{{ i18n.ts.save }}</button>
 	</div>
 </MkContainer>
@@ -19,7 +19,7 @@ SPDX-License-Identifier: AGPL-3.0-only
 import { ref, watch } from 'vue';
 import { useWidgetPropsManager } from './widget.js';
 import type { WidgetComponentEmits, WidgetComponentExpose, WidgetComponentProps } from './widget.js';
-import type { GetFormResultType } from '@/utility/form.js';
+import type { FormWithDefault, GetFormResultType } from '@/utility/form.js';
 import MkContainer from '@/components/MkContainer.vue';
 import { store } from '@/store.js';
 import { i18n } from '@/i18n.js';
@@ -28,14 +28,14 @@ const name = 'memo';
 
 const widgetPropsDef = {
 	showHeader: {
-		type: 'boolean' as const,
+		type: 'boolean',
 		default: true,
 	},
 	height: {
-		type: 'number' as const,
+		type: 'number',
 		default: 100,
 	},
-};
+} satisfies FormWithDefault;
 
 type WidgetProps = GetFormResultType<typeof widgetPropsDef>;
 
diff --git a/packages/frontend/src/widgets/WidgetNotifications.vue b/packages/frontend/src/widgets/WidgetNotifications.vue
index a1af5d084c..8fb7968238 100644
--- a/packages/frontend/src/widgets/WidgetNotifications.vue
+++ b/packages/frontend/src/widgets/WidgetNotifications.vue
@@ -17,9 +17,10 @@ SPDX-License-Identifier: AGPL-3.0-only
 
 <script lang="ts" setup>
 import { defineAsyncComponent } from 'vue';
+import type { notificationTypes as notificationTypes_typeReferenceOnly } from '@@/js/const.js';
 import { useWidgetPropsManager } from './widget.js';
 import type { WidgetComponentEmits, WidgetComponentExpose, WidgetComponentProps } from './widget.js';
-import type { GetFormResultType } from '@/utility/form.js';
+import type { FormWithDefault, GetFormResultType } from '@/utility/form.js';
 import MkContainer from '@/components/MkContainer.vue';
 import MkStreamingNotificationsTimeline from '@/components/MkStreamingNotificationsTimeline.vue';
 import * as os from '@/os.js';
@@ -29,19 +30,19 @@ const name = 'notifications';
 
 const widgetPropsDef = {
 	showHeader: {
-		type: 'boolean' as const,
+		type: 'boolean',
 		default: true,
 	},
 	height: {
-		type: 'number' as const,
+		type: 'number',
 		default: 300,
 	},
 	excludeTypes: {
-		type: 'array' as const,
+		type: 'array',
 		hidden: true,
-		default: [],
+		default: [] as (typeof notificationTypes_typeReferenceOnly[number])[],
 	},
-};
+} satisfies FormWithDefault;
 
 type WidgetProps = GetFormResultType<typeof widgetPropsDef>;
 
diff --git a/packages/frontend/src/widgets/WidgetOnlineUsers.vue b/packages/frontend/src/widgets/WidgetOnlineUsers.vue
index ce1871420a..9fd8c013d1 100644
--- a/packages/frontend/src/widgets/WidgetOnlineUsers.vue
+++ b/packages/frontend/src/widgets/WidgetOnlineUsers.vue
@@ -17,8 +17,8 @@ SPDX-License-Identifier: AGPL-3.0-only
 import { ref } from 'vue';
 import { useWidgetPropsManager } from './widget.js';
 import type { WidgetComponentEmits, WidgetComponentExpose, WidgetComponentProps } from './widget.js';
-import type { GetFormResultType } from '@/utility/form.js';
-import { misskeyApi, misskeyApiGet } from '@/utility/misskey-api.js';
+import type { FormWithDefault, GetFormResultType } from '@/utility/form.js';
+import { misskeyApiGet } from '@/utility/misskey-api.js';
 import { useInterval } from '@@/js/use-interval.js';
 import { i18n } from '@/i18n.js';
 import number from '@/filters/number.js';
@@ -27,10 +27,10 @@ const name = 'onlineUsers';
 
 const widgetPropsDef = {
 	transparent: {
-		type: 'boolean' as const,
+		type: 'boolean',
 		default: true,
 	},
-};
+} satisfies FormWithDefault;
 
 type WidgetProps = GetFormResultType<typeof widgetPropsDef>;
 
diff --git a/packages/frontend/src/widgets/WidgetPhotos.vue b/packages/frontend/src/widgets/WidgetPhotos.vue
index 6bbc52b2c2..e89a642b99 100644
--- a/packages/frontend/src/widgets/WidgetPhotos.vue
+++ b/packages/frontend/src/widgets/WidgetPhotos.vue
@@ -26,7 +26,7 @@ import { onUnmounted, ref } from 'vue';
 import * as Misskey from 'misskey-js';
 import { useWidgetPropsManager } from './widget.js';
 import type { WidgetComponentEmits, WidgetComponentExpose, WidgetComponentProps } from './widget.js';
-import type { GetFormResultType } from '@/utility/form.js';
+import type { FormWithDefault, GetFormResultType } from '@/utility/form.js';
 import { useStream } from '@/stream.js';
 import { getStaticImageUrl } from '@/utility/media-proxy.js';
 import { misskeyApi } from '@/utility/misskey-api.js';
@@ -38,14 +38,14 @@ const name = 'photos';
 
 const widgetPropsDef = {
 	showHeader: {
-		type: 'boolean' as const,
+		type: 'boolean',
 		default: true,
 	},
 	transparent: {
-		type: 'boolean' as const,
+		type: 'boolean',
 		default: false,
 	},
-};
+} satisfies FormWithDefault;
 
 type WidgetProps = GetFormResultType<typeof widgetPropsDef>;
 
diff --git a/packages/frontend/src/widgets/WidgetPostForm.vue b/packages/frontend/src/widgets/WidgetPostForm.vue
index 3170eab305..9f464cac95 100644
--- a/packages/frontend/src/widgets/WidgetPostForm.vue
+++ b/packages/frontend/src/widgets/WidgetPostForm.vue
@@ -11,13 +11,13 @@ SPDX-License-Identifier: AGPL-3.0-only
 import { } from 'vue';
 import { useWidgetPropsManager } from './widget.js';
 import type { WidgetComponentEmits, WidgetComponentExpose, WidgetComponentProps } from './widget.js';
-import type { GetFormResultType } from '@/utility/form.js';
+import type { FormWithDefault, GetFormResultType } from '@/utility/form.js';
 import MkPostForm from '@/components/MkPostForm.vue';
 
 const name = 'postForm';
 
 const widgetPropsDef = {
-};
+} satisfies FormWithDefault;
 
 type WidgetProps = GetFormResultType<typeof widgetPropsDef>;
 
diff --git a/packages/frontend/src/widgets/WidgetProfile.vue b/packages/frontend/src/widgets/WidgetProfile.vue
index 3fe8378a39..be149dae35 100644
--- a/packages/frontend/src/widgets/WidgetProfile.vue
+++ b/packages/frontend/src/widgets/WidgetProfile.vue
@@ -5,7 +5,7 @@ SPDX-License-Identifier: AGPL-3.0-only
 
 <template>
 <div class="_panel">
-	<div :class="$style.container" :style="{ backgroundImage: $i.bannerUrl ? `url(${ $i.bannerUrl })` : null }">
+	<div :class="$style.container" :style="{ backgroundImage: $i.bannerUrl ? `url(${ $i.bannerUrl })` : undefined }">
 		<div :class="$style.avatarContainer">
 			<MkAvatar :class="$style.avatar" :user="$i"/>
 		</div>
@@ -24,14 +24,16 @@ SPDX-License-Identifier: AGPL-3.0-only
 <script lang="ts" setup>
 import { useWidgetPropsManager } from './widget.js';
 import type { WidgetComponentEmits, WidgetComponentExpose, WidgetComponentProps } from './widget.js';
-import type { GetFormResultType } from '@/utility/form.js';
-import { $i } from '@/i.js';
+import type { FormWithDefault, GetFormResultType } from '@/utility/form.js';
+import { ensureSignin } from '@/i.js';
 import { userPage } from '@/filters/user.js';
 
+const $i = ensureSignin();
+
 const name = 'profile';
 
 const widgetPropsDef = {
-};
+} satisfies FormWithDefault;
 
 type WidgetProps = GetFormResultType<typeof widgetPropsDef>;
 
diff --git a/packages/frontend/src/widgets/WidgetRss.vue b/packages/frontend/src/widgets/WidgetRss.vue
index 2594262df1..e5499aa0da 100644
--- a/packages/frontend/src/widgets/WidgetRss.vue
+++ b/packages/frontend/src/widgets/WidgetRss.vue
@@ -26,7 +26,7 @@ import { url as base } from '@@/js/config.js';
 import { useInterval } from '@@/js/use-interval.js';
 import { useWidgetPropsManager } from './widget.js';
 import type { WidgetComponentEmits, WidgetComponentExpose, WidgetComponentProps } from './widget.js';
-import type { GetFormResultType } from '@/utility/form.js';
+import type { FormWithDefault, GetFormResultType } from '@/utility/form.js';
 import MkContainer from '@/components/MkContainer.vue';
 import { i18n } from '@/i18n.js';
 
@@ -34,22 +34,22 @@ const name = 'rss';
 
 const widgetPropsDef = {
 	url: {
-		type: 'string' as const,
+		type: 'string',
 		default: 'http://feeds.afpbb.com/rss/afpbb/afpbbnews',
 	},
 	refreshIntervalSec: {
-		type: 'number' as const,
+		type: 'number',
 		default: 60,
 	},
 	maxEntries: {
-		type: 'number' as const,
+		type: 'number',
 		default: 15,
 	},
 	showHeader: {
-		type: 'boolean' as const,
+		type: 'boolean',
 		default: true,
 	},
-};
+} satisfies FormWithDefault;
 
 type WidgetProps = GetFormResultType<typeof widgetPropsDef>;
 
diff --git a/packages/frontend/src/widgets/WidgetRssTicker.vue b/packages/frontend/src/widgets/WidgetRssTicker.vue
index 7fe7c6111a..9d4feb784c 100644
--- a/packages/frontend/src/widgets/WidgetRssTicker.vue
+++ b/packages/frontend/src/widgets/WidgetRssTicker.vue
@@ -32,7 +32,7 @@ import * as Misskey from 'misskey-js';
 import { useWidgetPropsManager } from './widget.js';
 import type { WidgetComponentEmits, WidgetComponentExpose, WidgetComponentProps } from './widget.js';
 import MarqueeText from '@/components/MkMarqueeText.vue';
-import type { GetFormResultType } from '@/utility/form.js';
+import type { FormWithDefault, GetFormResultType } from '@/utility/form.js';
 import MkContainer from '@/components/MkContainer.vue';
 import { shuffle } from '@/utility/shuffle.js';
 import { url as base } from '@@/js/config.js';
@@ -42,41 +42,41 @@ const name = 'rssTicker';
 
 const widgetPropsDef = {
 	url: {
-		type: 'string' as const,
+		type: 'string',
 		default: 'http://feeds.afpbb.com/rss/afpbb/afpbbnews',
 	},
 	shuffle: {
-		type: 'boolean' as const,
+		type: 'boolean',
 		default: true,
 	},
 	refreshIntervalSec: {
-		type: 'number' as const,
+		type: 'number',
 		default: 60,
 	},
 	maxEntries: {
-		type: 'number' as const,
+		type: 'number',
 		default: 15,
 	},
 	duration: {
-		type: 'range' as const,
+		type: 'range',
 		default: 70,
 		step: 1,
 		min: 5,
 		max: 200,
 	},
 	reverse: {
-		type: 'boolean' as const,
+		type: 'boolean',
 		default: false,
 	},
 	showHeader: {
-		type: 'boolean' as const,
+		type: 'boolean',
 		default: false,
 	},
 	transparent: {
-		type: 'boolean' as const,
+		type: 'boolean',
 		default: false,
 	},
-};
+} satisfies FormWithDefault;
 
 type WidgetProps = GetFormResultType<typeof widgetPropsDef>;
 
diff --git a/packages/frontend/src/widgets/WidgetSlideshow.vue b/packages/frontend/src/widgets/WidgetSlideshow.vue
index 3fe8cfa7e6..8e5dc9e8d3 100644
--- a/packages/frontend/src/widgets/WidgetSlideshow.vue
+++ b/packages/frontend/src/widgets/WidgetSlideshow.vue
@@ -22,7 +22,7 @@ import * as Misskey from 'misskey-js';
 import { useInterval } from '@@/js/use-interval.js';
 import { useWidgetPropsManager } from './widget.js';
 import type { WidgetComponentEmits, WidgetComponentExpose, WidgetComponentProps } from './widget.js';
-import type { GetFormResultType } from '@/utility/form.js';
+import type { FormWithDefault, GetFormResultType } from '@/utility/form.js';
 import * as os from '@/os.js';
 import { misskeyApi } from '@/utility/misskey-api.js';
 import { i18n } from '@/i18n.js';
@@ -32,15 +32,15 @@ const name = 'slideshow';
 
 const widgetPropsDef = {
 	height: {
-		type: 'number' as const,
+		type: 'number',
 		default: 300,
 	},
 	folderId: {
-		type: 'string' as const,
-		default: null,
+		type: 'string',
+		default: null as string | null,
 		hidden: true,
 	},
-};
+} satisfies FormWithDefault;
 
 type WidgetProps = GetFormResultType<typeof widgetPropsDef>;
 
@@ -59,7 +59,7 @@ const slideA = useTemplateRef('slideA');
 const slideB = useTemplateRef('slideB');
 
 const change = () => {
-	if (images.value.length === 0) return;
+	if (images.value.length === 0 || slideA.value == null || slideB.value == null) return;
 
 	const index = Math.floor(Math.random() * images.value.length);
 	const img = `url(${ images.value[index].url })`;
@@ -73,11 +73,12 @@ const change = () => {
 
 		slideA.value.style.backgroundImage = img;
 
-		slideB.value.classList.remove('anime');
+		slideB.value!.classList.remove('anime');
 	}, 1000);
 };
 
 const fetch = () => {
+	if (slideA.value == null || slideB.value == null) return;
 	fetching.value = true;
 
 	misskeyApi('drive/files', {
@@ -87,8 +88,8 @@ const fetch = () => {
 	}).then(res => {
 		images.value = res;
 		fetching.value = false;
-		slideA.value.style.backgroundImage = '';
-		slideB.value.style.backgroundImage = '';
+		slideA.value!.style.backgroundImage = '';
+		slideB.value!.style.backgroundImage = '';
 		change();
 	});
 };
diff --git a/packages/frontend/src/widgets/WidgetTimeline.vue b/packages/frontend/src/widgets/WidgetTimeline.vue
index 9cbeb9cf2e..6c775fd98c 100644
--- a/packages/frontend/src/widgets/WidgetTimeline.vue
+++ b/packages/frontend/src/widgets/WidgetTimeline.vue
@@ -12,7 +12,7 @@ SPDX-License-Identifier: AGPL-3.0-only
 	</template>
 	<template #header>
 		<button class="_button" @click="choose">
-			<span>{{ widgetProps.src === 'list' ? widgetProps.list.name : widgetProps.src === 'antenna' ? widgetProps.antenna.name : i18n.ts._timelines[widgetProps.src] }}</span>
+			<span>{{ headerTitle }}</span>
 			<i :class="menuOpened ? 'ti ti-chevron-up' : 'ti ti-chevron-down'" style="margin-left: 8px;"></i>
 		</button>
 	</template>
@@ -25,51 +25,59 @@ SPDX-License-Identifier: AGPL-3.0-only
 		<p :class="$style.disabledDescription">{{ i18n.ts._disabledTimeline.description }}</p>
 	</div>
 	<div v-else>
-		<MkStreamingNotesTimeline :key="widgetProps.src === 'list' ? `list:${widgetProps.list.id}` : widgetProps.src === 'antenna' ? `antenna:${widgetProps.antenna.id}` : widgetProps.src" :src="widgetProps.src" :list="widgetProps.list ? widgetProps.list.id : null" :antenna="widgetProps.antenna ? widgetProps.antenna.id : null"/>
+		<MkStreamingNotesTimeline
+			:key="widgetProps.src === 'list' ? `list:${widgetProps.list?.id}` : widgetProps.src === 'antenna' ? `antenna:${widgetProps.antenna?.id}` : widgetProps.src"
+			:src="widgetProps.src"
+			:list="widgetProps.list ? widgetProps.list.id : undefined"
+			:antenna="widgetProps.antenna ? widgetProps.antenna.id : undefined"
+		/>
 	</div>
 </MkContainer>
 </template>
 
 <script lang="ts" setup>
-import { ref } from 'vue';
+import { ref, computed } from 'vue';
+import * as Misskey from 'misskey-js';
 import { useWidgetPropsManager } from './widget.js';
 import type { WidgetComponentEmits, WidgetComponentExpose, WidgetComponentProps } from './widget.js';
-import type { GetFormResultType } from '@/utility/form.js';
+import type { FormWithDefault, GetFormResultType } from '@/utility/form.js';
 import * as os from '@/os.js';
 import { misskeyApi } from '@/utility/misskey-api.js';
 import MkContainer from '@/components/MkContainer.vue';
 import MkStreamingNotesTimeline from '@/components/MkStreamingNotesTimeline.vue';
 import { i18n } from '@/i18n.js';
-import { availableBasicTimelines, isAvailableBasicTimeline, isBasicTimeline, basicTimelineIconClass } from '@/timelines.js';
+import { availableBasicTimelines, isAvailableBasicTimeline, isBasicTimeline, basicTimelineIconClass, basicTimelineTypes } from '@/timelines.js';
 import type { MenuItem } from '@/types/menu.js';
 
 const name = 'timeline';
 
+type TlSrc = typeof basicTimelineTypes[number] | 'list' | 'antenna';
+
 const widgetPropsDef = {
 	showHeader: {
-		type: 'boolean' as const,
+		type: 'boolean',
 		default: true,
 	},
 	height: {
-		type: 'number' as const,
+		type: 'number',
 		default: 300,
 	},
 	src: {
-		type: 'string' as const,
-		default: 'home',
+		type: 'string',
+		default: 'home' as TlSrc,
 		hidden: true,
 	},
 	antenna: {
-		type: 'object' as const,
-		default: null,
+		type: 'object',
+		default: null as Misskey.entities.Antenna | null,
 		hidden: true,
 	},
 	list: {
-		type: 'object' as const,
-		default: null,
+		type: 'object',
+		default: null as Misskey.entities.UserList | null,
 		hidden: true,
 	},
-};
+} satisfies FormWithDefault;
 
 type WidgetProps = GetFormResultType<typeof widgetPropsDef>;
 
@@ -84,12 +92,22 @@ const { widgetProps, configure, save } = useWidgetPropsManager(name,
 
 const menuOpened = ref(false);
 
-const setSrc = (src) => {
+const headerTitle = computed<string>(() => {
+	if (widgetProps.src === 'list' && widgetProps.list != null) {
+		return widgetProps.list.name;
+	} else if (widgetProps.src === 'antenna' && widgetProps.antenna != null) {
+		return widgetProps.antenna.name;
+	} else {
+		return i18n.ts._timelines[widgetProps.src];
+	}
+});
+
+const setSrc = (src: TlSrc) => {
 	widgetProps.src = src;
 	save();
 };
 
-const choose = async (ev) => {
+const choose = async (ev: MouseEvent) => {
 	menuOpened.value = true;
 	const [antennas, lists] = await Promise.all([
 		misskeyApi('antennas/list'),
diff --git a/packages/frontend/src/widgets/WidgetTrends.vue b/packages/frontend/src/widgets/WidgetTrends.vue
index db09031c33..dcb900b0c9 100644
--- a/packages/frontend/src/widgets/WidgetTrends.vue
+++ b/packages/frontend/src/widgets/WidgetTrends.vue
@@ -29,7 +29,7 @@ import * as Misskey from 'misskey-js';
 import { useInterval } from '@@/js/use-interval.js';
 import { useWidgetPropsManager } from './widget.js';
 import type { WidgetComponentEmits, WidgetComponentExpose, WidgetComponentProps } from './widget.js';
-import type { GetFormResultType } from '@/utility/form.js';
+import type { FormWithDefault, GetFormResultType } from '@/utility/form.js';
 import MkContainer from '@/components/MkContainer.vue';
 import MkMiniChart from '@/components/MkMiniChart.vue';
 import { misskeyApiGet } from '@/utility/misskey-api.js';
@@ -40,10 +40,10 @@ const name = 'hashtags';
 
 const widgetPropsDef = {
 	showHeader: {
-		type: 'boolean' as const,
+		type: 'boolean',
 		default: true,
 	},
-};
+} satisfies FormWithDefault;
 
 type WidgetProps = GetFormResultType<typeof widgetPropsDef>;
 
diff --git a/packages/frontend/src/widgets/WidgetUnixClock.vue b/packages/frontend/src/widgets/WidgetUnixClock.vue
index f51ef12a2a..226a4c73aa 100644
--- a/packages/frontend/src/widgets/WidgetUnixClock.vue
+++ b/packages/frontend/src/widgets/WidgetUnixClock.vue
@@ -19,29 +19,29 @@ SPDX-License-Identifier: AGPL-3.0-only
 import { onUnmounted, ref, watch } from 'vue';
 import { useWidgetPropsManager } from './widget.js';
 import type { WidgetComponentEmits, WidgetComponentExpose, WidgetComponentProps } from './widget.js';
-import type { GetFormResultType } from '@/utility/form.js';
+import type { FormWithDefault, GetFormResultType } from '@/utility/form.js';
 
 const name = 'unixClock';
 
 const widgetPropsDef = {
 	transparent: {
-		type: 'boolean' as const,
+		type: 'boolean',
 		default: false,
 	},
 	fontSize: {
-		type: 'number' as const,
+		type: 'number',
 		default: 1.5,
 		step: 0.1,
 	},
 	showMs: {
-		type: 'boolean' as const,
+		type: 'boolean',
 		default: true,
 	},
 	showLabel: {
-		type: 'boolean' as const,
+		type: 'boolean',
 		default: true,
 	},
-};
+} satisfies FormWithDefault;
 
 type WidgetProps = GetFormResultType<typeof widgetPropsDef>;
 
@@ -54,7 +54,7 @@ const { widgetProps, configure } = useWidgetPropsManager(name,
 	emit,
 );
 
-let intervalId;
+let intervalId: number | null = null;
 const ss = ref('');
 const ms = ref('');
 const showColon = ref(false);
@@ -84,7 +84,10 @@ watch(() => widgetProps.showMs, () => {
 }, { immediate: true });
 
 onUnmounted(() => {
-	window.clearInterval(intervalId);
+	if (intervalId) {
+		window.clearInterval(intervalId);
+		intervalId = null;
+	}
 });
 
 defineExpose<WidgetComponentExpose>({
diff --git a/packages/frontend/src/widgets/WidgetUserList.vue b/packages/frontend/src/widgets/WidgetUserList.vue
index eb86732817..d87ea5ade2 100644
--- a/packages/frontend/src/widgets/WidgetUserList.vue
+++ b/packages/frontend/src/widgets/WidgetUserList.vue
@@ -28,7 +28,7 @@ import { ref } from 'vue';
 import * as Misskey from 'misskey-js';
 import { useWidgetPropsManager } from './widget.js';
 import type { WidgetComponentEmits, WidgetComponentExpose, WidgetComponentProps } from './widget.js';
-import type { GetFormResultType } from '@/utility/form.js';
+import type { FormWithDefault, GetFormResultType } from '@/utility/form.js';
 import MkContainer from '@/components/MkContainer.vue';
 import * as os from '@/os.js';
 import { misskeyApi } from '@/utility/misskey-api.js';
@@ -40,15 +40,15 @@ const name = 'userList';
 
 const widgetPropsDef = {
 	showHeader: {
-		type: 'boolean' as const,
+		type: 'boolean',
 		default: true,
 	},
 	listId: {
-		type: 'string' as const,
-		default: null,
+		type: 'string',
+		default: null as string | null,
 		hidden: true,
 	},
-};
+} satisfies FormWithDefault;
 
 type WidgetProps = GetFormResultType<typeof widgetPropsDef>;
 
@@ -61,7 +61,7 @@ const { widgetProps, configure, save } = useWidgetPropsManager(name,
 	emit,
 );
 
-const list = ref<Misskey.entities.UserList>();
+const list = ref<Misskey.entities.UserList | null>(null);
 const users = ref<Misskey.entities.UserDetailed[]>([]);
 const fetching = ref(true);
 
@@ -74,7 +74,7 @@ async function chooseList() {
 		})),
 		default: widgetProps.listId,
 	});
-	if (canceled) return;
+	if (canceled || list == null) return;
 
 	widgetProps.listId = list.id;
 	save();
@@ -92,7 +92,7 @@ const fetch = () => {
 	}).then(_list => {
 		list.value = _list;
 		misskeyApi('users/show', {
-			userIds: list.value.userIds,
+			userIds: list.value.userIds ?? [],
 		}).then(_users => {
 			users.value = _users;
 			fetching.value = false;
diff --git a/packages/frontend/src/widgets/server-metric/cpu-mem.vue b/packages/frontend/src/widgets/server-metric/cpu-mem.vue
index d8a876f936..fe86b73f99 100644
--- a/packages/frontend/src/widgets/server-metric/cpu-mem.vue
+++ b/packages/frontend/src/widgets/server-metric/cpu-mem.vue
@@ -80,7 +80,7 @@ import * as Misskey from 'misskey-js';
 import { genId } from '@/utility/id.js';
 
 const props = defineProps<{
-	connection: Misskey.ChannelConnection<Misskey.Channels['serverStats']>,
+	connection: Misskey.IChannelConnection<Misskey.Channels['serverStats']>,
 	meta: Misskey.entities.ServerInfoResponse
 }>();
 
diff --git a/packages/frontend/src/widgets/server-metric/cpu.vue b/packages/frontend/src/widgets/server-metric/cpu.vue
index ba98a926ff..99f502d94c 100644
--- a/packages/frontend/src/widgets/server-metric/cpu.vue
+++ b/packages/frontend/src/widgets/server-metric/cpu.vue
@@ -20,7 +20,7 @@ import * as Misskey from 'misskey-js';
 import XPie from './pie.vue';
 
 const props = defineProps<{
-	connection: Misskey.ChannelConnection<Misskey.Channels['serverStats']>,
+	connection: Misskey.IChannelConnection<Misskey.Channels['serverStats']>,
 	meta: Misskey.entities.ServerInfoResponse
 }>();
 
diff --git a/packages/frontend/src/widgets/server-metric/index.vue b/packages/frontend/src/widgets/server-metric/index.vue
index 9026fefb20..f52b6fd12e 100644
--- a/packages/frontend/src/widgets/server-metric/index.vue
+++ b/packages/frontend/src/widgets/server-metric/index.vue
@@ -14,7 +14,7 @@ SPDX-License-Identifier: AGPL-3.0-only
 		<XNet v-else-if="widgetProps.view === 1" :connection="connection" :meta="meta"/>
 		<XCpu v-else-if="widgetProps.view === 2" :connection="connection" :meta="meta"/>
 		<XMemory v-else-if="widgetProps.view === 3" :connection="connection" :meta="meta"/>
-		<XDisk v-else-if="widgetProps.view === 4" :connection="connection" :meta="meta"/>
+		<XDisk v-else-if="widgetProps.view === 4" :meta="meta"/>
 	</div>
 </MkContainer>
 </template>
@@ -30,7 +30,7 @@ import XCpu from './cpu.vue';
 import XMemory from './mem.vue';
 import XDisk from './disk.vue';
 import MkContainer from '@/components/MkContainer.vue';
-import type { GetFormResultType } from '@/utility/form.js';
+import type { FormWithDefault, GetFormResultType } from '@/utility/form.js';
 import { misskeyApiGet } from '@/utility/misskey-api.js';
 import { useStream } from '@/stream.js';
 import { i18n } from '@/i18n.js';
@@ -39,19 +39,19 @@ const name = 'serverMetric';
 
 const widgetPropsDef = {
 	showHeader: {
-		type: 'boolean' as const,
+		type: 'boolean',
 		default: true,
 	},
 	transparent: {
-		type: 'boolean' as const,
+		type: 'boolean',
 		default: false,
 	},
 	view: {
-		type: 'number' as const,
+		type: 'number',
 		default: 0,
 		hidden: true,
 	},
-};
+} satisfies FormWithDefault;
 
 type WidgetProps = GetFormResultType<typeof widgetPropsDef>;
 
diff --git a/packages/frontend/src/widgets/server-metric/mem.vue b/packages/frontend/src/widgets/server-metric/mem.vue
index ff4c6a44b4..089281b2ef 100644
--- a/packages/frontend/src/widgets/server-metric/mem.vue
+++ b/packages/frontend/src/widgets/server-metric/mem.vue
@@ -22,7 +22,7 @@ import XPie from './pie.vue';
 import bytes from '@/filters/bytes.js';
 
 const props = defineProps<{
-	connection: Misskey.ChannelConnection<Misskey.Channels['serverStats']>,
+	connection: Misskey.IChannelConnection<Misskey.Channels['serverStats']>,
 	meta: Misskey.entities.ServerInfoResponse
 }>();
 
diff --git a/packages/frontend/src/widgets/server-metric/net.vue b/packages/frontend/src/widgets/server-metric/net.vue
index 5e08a47100..38acd633a6 100644
--- a/packages/frontend/src/widgets/server-metric/net.vue
+++ b/packages/frontend/src/widgets/server-metric/net.vue
@@ -55,7 +55,7 @@ import bytes from '@/filters/bytes.js';
 import { genId } from '@/utility/id.js';
 
 const props = defineProps<{
-	connection: Misskey.ChannelConnection<Misskey.Channels['serverStats']>,
+	connection: Misskey.IChannelConnection<Misskey.Channels['serverStats']>,
 	meta: Misskey.entities.ServerInfoResponse
 }>();
 
diff --git a/packages/frontend/src/widgets/widget.ts b/packages/frontend/src/widgets/widget.ts
index de4c369cbb..c5ca7ac26c 100644
--- a/packages/frontend/src/widgets/widget.ts
+++ b/packages/frontend/src/widgets/widget.ts
@@ -4,8 +4,9 @@
  */
 
 import { reactive, watch } from 'vue';
+import type { Reactive } from 'vue';
 import { throttle } from 'throttle-debounce';
-import type { Form, GetFormResultType } from '@/utility/form.js';
+import type { FormWithDefault, GetFormResultType } from '@/utility/form.js';
 import * as os from '@/os.js';
 import { deepClone } from '@/utility/clone.js';
 
@@ -28,17 +29,17 @@ export type WidgetComponentExpose = {
 	configure: () => void;
 };
 
-export const useWidgetPropsManager = <F extends Form & Record<string, { default: any; }>>(
+export const useWidgetPropsManager = <F extends FormWithDefault>(
 	name: string,
 	propsDef: F,
 	props: Readonly<WidgetComponentProps<GetFormResultType<F>>>,
 	emit: WidgetComponentEmits<GetFormResultType<F>>,
 ): {
-	widgetProps: GetFormResultType<F>;
+	widgetProps: Reactive<GetFormResultType<F>>;
 	save: () => void;
 	configure: () => void;
 } => {
-	const widgetProps = reactive(props.widget ? deepClone(props.widget.data) : {});
+	const widgetProps = reactive<GetFormResultType<F>>((props.widget ? deepClone(props.widget.data) : {}) as GetFormResultType<F>);
 
 	const mergeProps = () => {
 		for (const prop of Object.keys(propsDef)) {
@@ -47,12 +48,13 @@ export const useWidgetPropsManager = <F extends Form & Record<string, { default:
 			}
 		}
 	};
+
 	watch(widgetProps, () => {
 		mergeProps();
 	}, { deep: true, immediate: true });
 
 	const save = throttle(3000, () => {
-		emit('updateProps', widgetProps);
+		emit('updateProps', widgetProps as GetFormResultType<F>);
 	});
 
 	const configure = async () => {