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@basham
Created May 5, 2023 15:17
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Integrate Lit's reactive controllers with React.
import { useEffect, useReducer, useRef } from 'react';
export class Controller {
#host;
constructor (host) {
this.#host = host;
host?.addController(this);
}
update () {
this.#host?.requestUpdate(this);
}
}
export function useController (Ctrl, ...args) {
const [, requestUpdate] = useReducer((x) => x + 1, 0);
const controllers = useRef(new Set()).current;
const addController = (controller) => controllers.add(controller);
const removeController = (controller) => controllers.delete(controller);
const callControllers = (property) => controllers.forEach((controller) => {
if (property in controller) {
controller[property]();
}
});
const host = { addController, removeController, requestUpdate: throttleRAF(requestUpdate) };
const controller = useRef(new Ctrl(host, ...args)).current;
useEffect(() => {
callControllers('hostConnected');
return () => callControllers('hostDisconnected');
}, []);
callControllers('hostUpdated');
return controller;
}
// Call the function at most once per animation frame.
function throttleRAF (fn) {
let wait = false;
return function (...args) {
if (wait) {
return;
}
wait = true;
window.requestAnimationFrame(() => {
fn.call(this, ...args);
wait = false;
});
}
}
@basham
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basham commented May 5, 2023

This follows most of the APIs outlined in the Lit Reactive Controller documentation.

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