npx create-react-app@next --scripts-version=@next --template=cra-template@next my-js-app
npx create-react-app@next --scripts-version=@next --template=typescript@next my-ts-app
To update an existing app you can change the react-scripts version in package.json to next and then run yarn or npm install
You can see a list of all the changes in the 4.0 release here
Tried out 4.0.0-next.98 today (coming from 3.4.3) in a medium-sized typescript monorepo. Our app builds and runs just fine.
Unfortunately some of our Jest tests broke. It looks like ts-jest is no longer getting used. Previously (with CRA3) we were able to specify a transform in the jest section of package.json like this:
"transform": {
"^.+\\.(js|jsx|ts|tsx)$": "<rootDir>/node_modules/ts-jest"
},This allowed us to use TypeScript features not supported by Babel (like emitDecoratorMetadata for TypeORM).
Looking at the v3.4.1...master diff, I'm not sure what broke it. Perhaps something about Jest 26?
Please do not report issues here. Open an issue in the repo so we can address them properly: https://github.com/facebook/create-react-app/issues
So excited about this! Can't wait to use Fast Refresh and new JSX transform ⚛️
I've got an error referencing images from public folder in css files. It was working fine in the latest stable version. Are there any configurations I should change?
background: url("/assets/arrow.svg"); /* Compile error: Can't resolve '/assets/arrow.svg' */