refactor(frontend): page-metadata -> page

packages/frontend/src/page.ts

@@ -0,0 +1,71 @@
+/*
+ * SPDX-FileCopyrightText: syuilo and misskey-project
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+
+import * as Misskey from 'misskey-js';
+import { inject, isRef, onActivated, onBeforeUnmount, provide, ref, toValue, watch } from 'vue';
+import type { MaybeRefOrGetter, Ref } from 'vue';
+
+export type PageMetadata = {
+	title: string;
+	subtitle?: string;
+	icon?: string | null;
+	avatar?: Misskey.entities.User | null;
+	userName?: Misskey.entities.User | null;
+	needWideArea?: boolean;
+};
+
+type PageMetadataGetter = () => PageMetadata;
+type PageMetadataReceiver = (getter: PageMetadataGetter) => void;
+
+const RECEIVER_KEY = Symbol('ReceiverKey');
+const setReceiver = (v: PageMetadataReceiver): void => {
+	provide<PageMetadataReceiver>(RECEIVER_KEY, v);
+};
+const getReceiver = (): PageMetadataReceiver | undefined => {
+	return inject<PageMetadataReceiver>(RECEIVER_KEY);
+};
+
+const METADATA_KEY = Symbol('MetadataKey');
+const setMetadata = (v: Ref<PageMetadata | null>): void => {
+	provide<Ref<PageMetadata | null>>(METADATA_KEY, v);
+};
+const getMetadata = (): Ref<PageMetadata | null> | undefined => {
+	return inject<Ref<PageMetadata | null>>(METADATA_KEY);
+};
+
+export const definePage = (maybeRefOrGetterMetadata: MaybeRefOrGetter<PageMetadata>): void => {
+	const metadataRef = ref(toValue(maybeRefOrGetterMetadata));
+	const metadataGetter = () => metadataRef.value;
+	const receiver = getReceiver();
+
+	// setup handler
+	receiver?.(metadataGetter);
+
+	// update handler
+	onBeforeUnmount(watch(
+		() => toValue(maybeRefOrGetterMetadata),
+		(metadata) => {
+			metadataRef.value = metadata;
+			receiver?.(metadataGetter);
+		},
+		{ deep: true },
+	));
+	onActivated(() => {
+		receiver?.(metadataGetter);
+	});
+};
+
+export const provideMetadataReceiver = (receiver: PageMetadataReceiver): void => {
+	setReceiver(receiver);
+};
+
+export const provideReactiveMetadata = (metadataRef: Ref<PageMetadata | null>): void => {
+	setMetadata(metadataRef);
+};
+
+export const injectReactiveMetadata = (): Ref<PageMetadata | null> => {
+	const metadataRef = getMetadata();
+	return isRef(metadataRef) ? metadataRef : ref(null);
+};