1 files changed, 49 insertions, 0 deletions
diff --git a/packages/frontend-embed/src/post-message.ts b/packages/frontend-embed/src/post-message.ts
new file mode 100644
index 0000000000..fd8eb8a5d2
--- /dev/null
+++ b/packages/frontend-embed/src/post-message.ts
@@ -0,0 +1,49 @@
+/*
+ * SPDX-FileCopyrightText: syuilo and misskey-project
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+
+export const postMessageEventTypes = [
+	'misskey:embed:ready',
+	'misskey:embed:changeHeight',
+] as const;
+
+export type PostMessageEventType = typeof postMessageEventTypes[number];
+
+export interface PostMessageEventPayload extends Record<PostMessageEventType, any> {
+	'misskey:embed:ready': undefined;
+	'misskey:embed:changeHeight': {
+		height: number;
+	};
+}
+
+export type MiPostMessageEvent<T extends PostMessageEventType = PostMessageEventType> = {
+	type: T;
+	iframeId?: string;
+	payload?: PostMessageEventPayload[T];
+}
+
+let defaultIframeId: string | null = null;
+
+export function setIframeId(id: string): void {
+	if (defaultIframeId != null) return;
+
+	if (_DEV_) console.log('setIframeId', id);
+	defaultIframeId = id;
+}
+
+/**
+ * 親フレームにイベントを送信
+ */
+export function postMessageToParentWindow<T extends PostMessageEventType = PostMessageEventType>(type: T, payload?: PostMessageEventPayload[T], iframeId: string | null = null): void {
+	let _iframeId = iframeId;
+	if (_iframeId == null) {
+		_iframeId = defaultIframeId;
+	}
+	if (_DEV_) console.log('postMessageToParentWindow', type, _iframeId, payload);
+	window.parent.postMessage({
+		type,
+		iframeId: _iframeId,
+		payload,
+	}, '*');
+}