React custom hooks for web workers.
Web Workers are another thread from the main thread in browsers. We can run heavy computation in a separate thread so that users don't feel slowing down.
React provides a reactive system. This library hides the async nature of Web Workers with React custom hooks. Results returned by Web Workers are stored in a React local state.
Developers can implement a worker as:
npm install react-hooks-worker
slow_fib.worker.js:
import { exposeWorker } from 'react-hooks-worker';
const fib = i => (i <= 1 ? i : fib(i - 1) + fib(i - 2));
exposeWorker(fib);
app.js:
import React from 'react';
import { useWorker } from 'react-hooks-worker';
const createWorker = () => new Worker(
new URL('./slow_fib.worker', import.meta.url),
{ type: 'module' }
);
const CalcFib = ({ count }) => {
const { result, error } = useWorker(createWorker, count);
if (error) return <div>Error: {error}</div>;
return <div>Result: {result}</div>;
};
const App = () => (
<div>
<CalcFib count={5} />
</div>
);
The communication between main thread and worker thread is not RPC model. It can be one input to return multiple outputs, or multiple inputs to get one output.
Handling pending or stale status is left for library users.
Refer #44
for a recipe for isStale
.
expose worker
You can expose any function that returns:
func
function (data: any): any getOptions
function (): WindowPostMessageOptions? import { exposeWorker } from 'react-hooks-worker';
const fib = (i) => (i <= 1 ? i : fib(i - 1) + fib(i - 2));
exposeWorker(fib);
use worker
The createWorker function should be stable to keep the worker running. If it's referentially changed, it will create a new worker and terminate the old one.
createWorker
function (): Worker input
Input getOptions
function (): WindowPostMessageOptions? import { useWorker } from 'react-hooks-worker';
const createWorker = () => new Worker(
new URL('./slow_fib.worker', import.meta.url),
{ type: 'module' }
);
const CalcFib = ({ count }) => {
const { result, error } = useWorker(createWorker, count);
if (error) return <div>Error: {error}</div>;
return <div>Result: {result}</div>;
};
The examples folder contains working examples. You can run one of them with
PORT=8080 npm run examples:01_minimal
and open http://localhost:8080 in your web browser.