Marc Wieland
33181acf83
Some checks are pending
Deploy Volleyball CMS / deploy (push) Waiting to run
65 lines
2.3 KiB
TypeScript
65 lines
2.3 KiB
TypeScript
/*
|
|
* Copyright 2020 Adobe. All rights reserved.
|
|
* This file is licensed to you under the Apache License, Version 2.0 (the "License");
|
|
* you may not use this file except in compliance with the License. You may obtain a copy
|
|
* of the License at http://www.apache.org/licenses/LICENSE-2.0
|
|
*
|
|
* Unless required by applicable law or agreed to in writing, software distributed under
|
|
* the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR REPRESENTATIONS
|
|
* OF ANY KIND, either express or implied. See the License for the specific language
|
|
* governing permissions and limitations under the License.
|
|
*/
|
|
|
|
import {Dispatch, MutableRefObject, useRef, useState} from 'react';
|
|
import {useEffectEvent, useLayoutEffect} from './';
|
|
|
|
type SetValueAction<S> = (prev: S) => Generator<any, void, unknown>;
|
|
|
|
// This hook works like `useState`, but when setting the value, you pass a generator function
|
|
// that can yield multiple values. Each yielded value updates the state and waits for the next
|
|
// layout effect, then continues the generator. This allows sequential updates to state to be
|
|
// written linearly.
|
|
export function useValueEffect<S>(defaultValue: S | (() => S)): [S, Dispatch<SetValueAction<S>>] {
|
|
let [value, setValue] = useState(defaultValue);
|
|
let effect: MutableRefObject<Generator<S> | null> = useRef<Generator<S> | null>(null);
|
|
|
|
// Store the function in a ref so we can always access the current version
|
|
// which has the proper `value` in scope.
|
|
let nextRef = useEffectEvent(() => {
|
|
if (!effect.current) {
|
|
return;
|
|
}
|
|
// Run the generator to the next yield.
|
|
let newValue = effect.current.next();
|
|
|
|
// If the generator is done, reset the effect.
|
|
if (newValue.done) {
|
|
effect.current = null;
|
|
return;
|
|
}
|
|
|
|
// If the value is the same as the current value,
|
|
// then continue to the next yield. Otherwise,
|
|
// set the value in state and wait for the next layout effect.
|
|
if (value === newValue.value) {
|
|
nextRef();
|
|
} else {
|
|
setValue(newValue.value);
|
|
}
|
|
});
|
|
|
|
useLayoutEffect(() => {
|
|
// If there is an effect currently running, continue to the next yield.
|
|
if (effect.current) {
|
|
nextRef();
|
|
}
|
|
});
|
|
|
|
let queue = useEffectEvent(fn => {
|
|
effect.current = fn(value);
|
|
nextRef();
|
|
});
|
|
|
|
return [value, queue];
|
|
}
|