# `` [![npm version](https://img.shields.io/npm/v/react-webworker.svg)](https://www.npmjs.com/package/react-webworker) [![npm downloads](https://img.shields.io/npm/dm/react-webworker.svg)](https://www.npmjs.com/package/react-webworker) [![minified size](https://img.shields.io/bundlephobia/min/react-webworker.svg)](https://bundlephobia.com/result?p=react-webworker) [![Build status](https://img.shields.io/travis/ghengeveld/react-webworker.svg)](https://travis-ci.org/ghengeveld/react-webworker) [![Code coverage](https://img.shields.io/codecov/c/github/ghengeveld/react-webworker.svg)](https://codecov.io/github/ghengeveld/react-webworker) [![ISC license](https://img.shields.io/npm/l/react-webworker.svg)](https://opensource.org/licenses/ISC) [![GitHub issues](https://img.shields.io/github/issues/ghengeveld/react-webworker.svg)](https://github.com/ghengeveld/react-webworker/issues) [![GitHub PRs](https://img.shields.io/github/issues-pr/ghengeveld/react-webworker.svg)](https://github.com/ghengeveld/react-webworker/pulls) React component for easy communication with a Web Worker. Leverages the Render Props pattern for ultimate flexibility as well as the new Context API for ease of use. Just specify the public url to your Web Worker and you'll get access to any messages or errors it sends, as well as the `postMessage` handler. Also works with Service Workers. - Zero dependencies - Choose between Render Props and Context-based helper components - Provides timestamped `messages` and `errors` - Provides easy access to the last message `data` and last `error` - Provides `postMessage` to send messages to the Web Worker - Provides `updatedAt` and `lastPostAt` metadata - Accepts `parser` and `serializer` for automatic message (de)serialization - Accepts `onMessage` and `onError` callbacks - Supports custom Worker instance through the `worker` prop **(new in v2)** - Supports communication with Service Workers **(new in v2.1)** > This package was modeled after [``](https://github.com/ghengeveld/react-async) which helps you deal with Promises in React. ## Install ``` npm install --save react-webworker ``` ## Usage Using render props for ultimate flexibility: ```js import WebWorker from "react-webworker" const MyComponent = () => ( {({ data, error, postMessage }) => { if (error) return `Something went wrong: ${error.message}` if (data) return (

Received some data:

{JSON.stringify(data, null, 2)}

) return }} ) ``` Using helper components (don't have to be direct children) for ease of use: ```js import WebWorker from "react-webworker" const MyComponent = () => ( {({ postMessage }) => } {data => (

Received some data:

{JSON.stringify(data, null, 2)}

)} {error => `Something went wrong: ${error.message}`} ) ``` ### Usage with Parcel or `worker-plugin` for Webpack [Parcel](https://parceljs.org) and [worker-plugin](https://npm.im/worker-plugin) allow your Web Worker script to be automatically bundled. However this only works when you create the Worker instance yourself, instead of having react-webworker do it for you. Here's how that works: ```js import WebWorker from "react-webworker" const myWorker = new Worker("./worker.js") // relative path to the source file, not the public URL const MyComponent = () => ... ``` The downside to this approach is that `` will not manage the Worker's lifecycle. This means it will not automatically be terminated when `` is unmounted. ### Communicating with a Service Worker Using `` with a Service Worker is as simple as passing it as a custom worker instance: ```js const MyComponent = () => ... ``` This will automatically setup a `MessageChannel` to enable bidirectional communication. Your Service Worker could look like this: ```js // `ports` is automatically provided with a MessageChannel port self.onmessage = ({ data, ports: [port] }) => { console.log("inside the service worker:", data) port.postMessage(data) // instead of `self.postMessage` } ``` Note that messages sent to an inactive (not "activated") Service Worker will be silently ignored. Like a custom Worker, you'll have to deal with the Service Worker lifecycle yourself. ## API ### Props `` takes the following properties: - `url` {string} (required) Public url to the Web Worker file (or path relative to the root of your domain) - `options` {Object} Options passed to the Worker constructor - `worker` {Worker} An existing Worker instance to use instead of creating a new one (ignoring `url` and `options`) - `parser` {Function} Transforms incoming message data (not errors) - `serializer` {Function} Transforms `postMessage` payload before sending - `onMessage` {Function} Callback function invoked when a message is received, passing message data as argument - `onError` {Function} Callback function invoked when an error is received, passing error object as argument > `url` and `options` are evaluated at mount time, so they must be defined immediately and won't respond to changes. > A custom Worker provided through `worker` will not get terminated on unmount. You'll have to manage its lifecycle yourself. ### Render props `` provides the following render props: - `messages` {Array} list of received messages ({ data, date }), in chronological order - `errors` {Array} list of received errors ({ error, date }), in chronological order - `data` {any} last received message data, maintained when an error is received - `error` {Error} last received error, cleared when new message arrives - `updatedAt` {Date} when the last message or error was received - `postMessage` {Function} sends a message to the Web Worker > Note: [it's recommended](https://nolanlawson.com/2016/02/29/high-performance-web-worker-messages/) to send and receive > JSON strings instead of JS objects for improved performance. You can use the `parser` and `serializer` props to have > `` deal with this on the client side, but your Worker must still (de)serialize messages on its end. ## Examples ### Using `lastPostAt` to show a loading indicator ```js import WebWorker from "react-webworker" const MyComponent = () => ( {({ data, error, postMessage, updatedAt, lastPostAt }) => (

{data && (

Received some data:

{JSON.stringify(data, null, 2)}

)}

)} ) ``` ### Passing options to the Worker ```js import WebWorker from "react-webworker" const MyComponent = () => ( ... ) ``` ### Using `parser` and `serializer` to automatically parse incoming messages and stringify outgoing messages ```js import WebWorker from "react-webworker" const MyComponent = () => ( {({ data, error, postMessage, updatedAt, lastPostAt }) => (

{data && (

Received some data:

{JSON.stringify(data, null, 2)}

)}

)} ) ``` > Note: the Worker must still implement JSON (de)serialization on its own end. ## Helper components `` provides several helper components that make your JSX even more declarative. They don't have to be direct children of `` and you can use the same component several times. ### `` Renders only when a message has been received. #### Props - `children` {Function|Node} Render function which receives last message data and props object or just a plain React node. #### Examples ```js {data =>

{JSON.stringify(data)}

} ``` ### `` Renders only when an error has been received. #### Props - `children` {Function|Node} Render function which receives error and props object or just a plain React node. #### Examples ```js {error => `Unexpected error: ${error.message}`} ``` ### `` Renders only when no message or error has been received yet. Enable `persist` to ignore errors. #### Props - `persist` {boolean} Show until we receive message data, even when an error is received. - `children` {Function|Node} Function which receives props object or React node.

	Stars	Issues	Version	Updated	Created
@koale/useworker	2,888	34	4.0.2	3 years ago	4 years ago
react-webworker			2.1.0	6 years ago	6 years ago
webworker			0.8.4	13 years ago	13 years ago
webworker-threads	2,291	69	0.7.17	6 years ago	11 years ago

@koale/useworker vs react-webworker vs webworker vs webworker-threads

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