Created
April 12, 2023 14:26
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| import { useMemo, useRef } from "react"; | |
| import type { MutableRefObject, RefObject } from "react"; | |
| export interface AsyncMutableRefObject<T> extends MutableRefObject<T> { | |
| readonly asyncCurrent: Promise<Exclude<T, null | undefined>>; | |
| } | |
| export interface AsyncRefObject<T> extends RefObject<T> { | |
| readonly asyncCurrent: Promise<Exclude<T, null | undefined>>; | |
| } | |
| export function useAsyncRef<T>(initialValue: T): AsyncMutableRefObject<T>; | |
| export function useAsyncRef<T>(initialValue: T | null): AsyncRefObject<T>; | |
| export function useAsyncRef<T = undefined>(): AsyncMutableRefObject< | |
| T | undefined | |
| >; | |
| export function useAsyncRef<T>(obj?: T | null) { | |
| const pendingAwaits = useRef<any[]>([]); | |
| const ref = useRef(obj); | |
| const handler: ProxyHandler<typeof ref> = useMemo( | |
| () => ({ | |
| get(target, prop, receiver) { | |
| if (prop !== "asyncCurrent") return Reflect.get(target, prop, receiver); | |
| const getTarget = async () => { | |
| if ( | |
| target.current !== null && | |
| typeof target.current !== "undefined" | |
| ) { | |
| return target.current; | |
| } | |
| const current = await new Promise((resolve) => | |
| pendingAwaits.current.push(resolve) | |
| ); | |
| return current; | |
| }; | |
| return getTarget(); | |
| }, | |
| set(target, p, newValue) { | |
| if (p !== "current") return Reflect.set(target, p, newValue); | |
| try { | |
| return Reflect.set(target, p, newValue); | |
| } finally { | |
| if (newValue !== null && typeof newValue !== "undefined") { | |
| while (pendingAwaits.current.length) { | |
| const resolve = pendingAwaits.current.pop(); | |
| resolve(target.current); | |
| } | |
| } | |
| } | |
| }, | |
| }), | |
| [] | |
| ); | |
| return useMemo(() => new Proxy(ref, handler), [handler]); | |
| } |
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