52 lines
1.3 KiB
JavaScript
52 lines
1.3 KiB
JavaScript
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import { useEffect, useState } from 'react';
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import { addHook } from './components/SingletonHooksContainer';
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import { batch } from './utils/env';
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export const singletonHook = (initValue, useHookBody, unmount = false) => {
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let mounted = false;
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let removeHook = undefined
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let initStateCalculated = false;
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let lastKnownState = undefined;
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let consumers = [];
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const applyStateChange = (newState) => {
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lastKnownState = newState;
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batch(() => consumers.forEach(c => c(newState)));
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};
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const stateInitializer = () => {
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if (!initStateCalculated) {
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lastKnownState = typeof initValue === 'function' ? initValue() : initValue;
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initStateCalculated = true;
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}
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return lastKnownState;
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};
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return () => {
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const [state, setState] = useState(stateInitializer);
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useEffect(() => {
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if (!mounted) {
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mounted = true;
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removeHook = addHook({ initValue, useHookBody, applyStateChange });
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}
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consumers.push(setState);
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if (lastKnownState !== state) {
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setState(lastKnownState);
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}
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return () => {
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consumers.splice(consumers.indexOf(setState), 1);
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if (consumers.length === 0 && unmount) {
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removeHook();
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mounted = false;
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}
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};
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// eslint-disable-next-line react-hooks/exhaustive-deps
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}, []);
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return state;
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};
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};
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