https://github.com/bryik/cra-web-workers
Demonstrates how to have web workers in a create-react-app project.
https://github.com/bryik/cra-web-workers
create-react-app web-worker
Last synced: over 1 year ago
JSON representation
Demonstrates how to have web workers in a create-react-app project.
- Host: GitHub
- URL: https://github.com/bryik/cra-web-workers
- Owner: bryik
- Created: 2020-11-02T02:45:54.000Z (over 5 years ago)
- Default Branch: main
- Last Pushed: 2020-11-02T03:36:55.000Z (over 5 years ago)
- Last Synced: 2025-01-19T23:32:48.789Z (over 1 year ago)
- Topics: create-react-app, web-worker
- Language: JavaScript
- Homepage: https://cra-web-workers.netlify.app/
- Size: 192 KB
- Stars: 0
- Watchers: 2
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
Awesome Lists containing this project
README
# cra-web-workers
[](https://app.netlify.com/sites/cra-web-workers/deploys)
This is a demonstration of using [worker-loader](https://github.com/webpack-contrib/worker-loader) to run a web worker in a create-react-app project.
See [this issue thread](https://github.com/facebook/create-react-app/pull/5886) and [this article](https://dev.to/nicolasrannou/web-workers-in-create-react-app-cra-without-unmounting-4865) for more details.
## why is this useful?
`create-react-app` does not currently support web workers (the Webpack config is not setup for it or something). However, [worker-loader](https://github.com/webpack-contrib/worker-loader) can be inlined (side-stepping the need to eject from CRA).
## how does it work?
Tracing a click of the increment button:
1. [The increment button](https://github.com/bryik/cra-web-workers/blob/main/src/components/Counter.js#L41) is clicked causing the [`onClick` handler](https://github.com/bryik/cra-web-workers/blob/main/src/components/Counter.js#L9) to be called.
2. The `onClick` handler calls [`worker.postMessage()`](https://github.com/bryik/cra-web-workers/blob/main/src/components/Counter.js#L11) with an object describing what the worker should do: `{ type: "increment" }`.
3. The worker, in its separate thread, receives the message which triggers the [`onmessage()` handler](https://github.com/bryik/cra-web-workers/blob/main/src/workers/CounterWorker.js#L5). The `onmessage()` handler looks at `{ type: "increment" }` and determines that the [`increment()` function](https://github.com/bryik/cra-web-workers/blob/main/src/workers/CounterWorker.js#L2) should be called. After `increment()` is called, the worker calls `postMessage()` to inform the main thread of the new count: `{ type: "update", count }`.
4. The main thread receives the message in the [`newWorker.onmessage()` handler](https://github.com/bryik/cra-web-workers/blob/main/src/components/Counter.js#L22), interprets it, and finally calls [`setCount()`](https://github.com/bryik/cra-web-workers/blob/main/src/components/Counter.js#L26) which updates the component's local state.
5. `` is re-rendered, the new count is displayed.
It is silly to offload quick calculations like this to a worker, but this is just a demo.
## Available Scripts
In the project directory, you can run:
### `npm start`
Runs the app in the development mode.\
Open [http://localhost:3000](http://localhost:3000) to view it in the browser.
The page will reload if you make edits.\
You will also see any lint errors in the console.
### `npm test`
Launches the test runner in the interactive watch mode.\
See the section about [running tests](https://facebook.github.io/create-react-app/docs/running-tests) for more information.
### `npm run build`
Builds the app for production to the `build` folder.\
It correctly bundles React in production mode and optimizes the build for the best performance.
The build is minified and the filenames include the hashes.\
Your app is ready to be deployed!
See the section about [deployment](https://facebook.github.io/create-react-app/docs/deployment) for more information.
### `npm run eject`
**Note: this is a one-way operation. Once you `eject`, you can’t go back!**
If you aren’t satisfied with the build tool and configuration choices, you can `eject` at any time. This command will remove the single build dependency from your project.
Instead, it will copy all the configuration files and the transitive dependencies (webpack, Babel, ESLint, etc) right into your project so you have full control over them. All of the commands except `eject` will still work, but they will point to the copied scripts so you can tweak them. At this point you’re on your own.
You don’t have to ever use `eject`. The curated feature set is suitable for small and middle deployments, and you shouldn’t feel obligated to use this feature. However we understand that this tool wouldn’t be useful if you couldn’t customize it when you are ready for it.
## Learn More
You can learn more in the [Create React App documentation](https://facebook.github.io/create-react-app/docs/getting-started).
To learn React, check out the [React documentation](https://reactjs.org/).
### Code Splitting
This section has moved here: [https://facebook.github.io/create-react-app/docs/code-splitting](https://facebook.github.io/create-react-app/docs/code-splitting)
### Analyzing the Bundle Size
This section has moved here: [https://facebook.github.io/create-react-app/docs/analyzing-the-bundle-size](https://facebook.github.io/create-react-app/docs/analyzing-the-bundle-size)
### Making a Progressive Web App
This section has moved here: [https://facebook.github.io/create-react-app/docs/making-a-progressive-web-app](https://facebook.github.io/create-react-app/docs/making-a-progressive-web-app)
### Advanced Configuration
This section has moved here: [https://facebook.github.io/create-react-app/docs/advanced-configuration](https://facebook.github.io/create-react-app/docs/advanced-configuration)
### Deployment
This section has moved here: [https://facebook.github.io/create-react-app/docs/deployment](https://facebook.github.io/create-react-app/docs/deployment)
### `npm run build` fails to minify
This section has moved here: [https://facebook.github.io/create-react-app/docs/troubleshooting#npm-run-build-fails-to-minify](https://facebook.github.io/create-react-app/docs/troubleshooting#npm-run-build-fails-to-minify)