39 lines
1.1 KiB
TypeScript
39 lines
1.1 KiB
TypeScript
import { useEffect, useRef, useState } from "react";
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export default function useMemoSingleThreaded<T>(
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fn: () => T | Promise<T>,
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deps: any[],
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): T {
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const [result, setResult] = useState<T>(null);
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const updateInProgress = useRef(false);
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const updateRequired = useRef(false);
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useEffect(() => {
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const main = async () => {
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if (updateInProgress.current) {
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updateRequired.current = true;
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return;
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}
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updateInProgress.current = true;
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const result = fn();
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if (isPromise(result)) {
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const resultValue = await result;
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setResult(resultValue);
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} else {
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setResult(result);
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}
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updateInProgress.current = false;
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if (updateRequired.current) {
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updateRequired.current = false;
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setTimeout(main, 0);
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}
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};
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main();
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}, deps);
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return result;
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}
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function isPromise<T>(obj: T | Promise<T>): obj is Promise<T> {
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return obj && typeof (obj as any).then === "function";
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}
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