--- id: adding-flow title: Adding Flow --- Flow is a static type checker that helps you write code with fewer bugs. Check out this [introduction to using static types in JavaScript](https://medium.com/@preethikasireddy/why-use-static-types-in-javascript-part-1-8382da1e0adb) if you are new to this concept. Recent versions of [Flow](https://flow.org/) work with Create React App projects out of the box. To add Flow to a Create React App project, follow these steps: 1. Run `npm install --save flow-bin` (or `yarn add flow-bin`). 2. Add `"flow": "flow"` to the `scripts` section of your `package.json`. 3. Run `npm run flow init` (or `yarn flow init`) to create a [`.flowconfig` file](https://flow.org/en/docs/config/) in the root directory. 4. Add `// @flow` to any files you want to type check (for example, to `src/App.js`). Now you can run `npm run flow` (or `yarn flow`) to check the files for type errors. You can optionally use an IDE like [Nuclide](https://nuclide.io/docs/languages/flow/) for a better integrated experience. In the future we plan to integrate it into Create React App even more closely. To learn more about Flow, check out [its documentation](https://flow.org/).