next
Version:
The React Framework
53 lines (52 loc) • 2.09 kB
JavaScript
import { Children, useEffect, useLayoutEffect } from 'react';
const isServer = typeof window === 'undefined';
const useClientOnlyLayoutEffect = isServer ? ()=>{} : useLayoutEffect;
const useClientOnlyEffect = isServer ? ()=>{} : useEffect;
export default function SideEffect(props) {
const { headManager, reduceComponentsToState } = props;
function emitChange() {
if (headManager && headManager.mountedInstances) {
const headElements = Children.toArray(Array.from(headManager.mountedInstances).filter(Boolean));
headManager.updateHead(reduceComponentsToState(headElements));
}
}
if (isServer) {
headManager?.mountedInstances?.add(props.children);
emitChange();
}
useClientOnlyLayoutEffect(()=>{
headManager?.mountedInstances?.add(props.children);
return ()=>{
headManager?.mountedInstances?.delete(props.children);
};
});
// We need to call `updateHead` method whenever the `SideEffect` is trigger in all
// life-cycles: mount, update, unmount. However, if there are multiple `SideEffect`s
// being rendered, we only trigger the method from the last one.
// This is ensured by keeping the last unflushed `updateHead` in the `_pendingUpdate`
// singleton in the layout effect pass, and actually trigger it in the effect pass.
useClientOnlyLayoutEffect(()=>{
if (headManager) {
headManager._pendingUpdate = emitChange;
}
return ()=>{
if (headManager) {
headManager._pendingUpdate = emitChange;
}
};
});
useClientOnlyEffect(()=>{
if (headManager && headManager._pendingUpdate) {
headManager._pendingUpdate();
headManager._pendingUpdate = null;
}
return ()=>{
if (headManager && headManager._pendingUpdate) {
headManager._pendingUpdate();
headManager._pendingUpdate = null;
}
};
});
return null;
}
//# sourceMappingURL=side-effect.js.map