42 lines
819 B
TypeScript
42 lines
819 B
TypeScript
type HookFn = () => void;
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interface HookFilter {
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fn: HookFn;
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}
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/**
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* Simple React hookable store with manual change notifications
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*/
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export default abstract class ExternalStore<TSnapshot> {
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#hooks: Array<HookFilter> = [];
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#snapshot: Readonly<TSnapshot> = {} as Readonly<TSnapshot>;
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#changed = true;
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hook(fn: HookFn) {
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this.#hooks.push({
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fn,
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});
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return () => {
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const idx = this.#hooks.findIndex(a => a.fn === fn);
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if (idx >= 0) {
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this.#hooks.splice(idx, 1);
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}
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};
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}
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snapshot() {
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if (this.#changed) {
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this.#snapshot = this.takeSnapshot();
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this.#changed = false;
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}
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return this.#snapshot;
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}
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protected notifyChange() {
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this.#changed = true;
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this.#hooks.forEach(h => h.fn());
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}
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abstract takeSnapshot(): TSnapshot;
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}
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