How to set build .env variables when running create-react-app build script?

Question

I\'m using the following environment variable in my create-react-app:

console.log(process.env.REACT_APP_API_URL) // http://localhost:5555

I

Answer 1

You can use the process.env.NODE_ENV like so:

const apiUrl = process.env.NODE_ENV === 'production' ? process.env.REACT_APP_PROD_API_URL : process.env.REACT_APP_DEV_API_URL;

You would need to have REACT_APP_PROD_API_URL and REACT_APP_DEV_API_URL set.

Or, if the production URL is always the same, you could simplify it:

const apiUrl = process.env.NODE_ENV === 'production' ? 'https://example.com' : process.env.REACT_APP_DEV_API_URL;

Create React App sets the NODE_ENV to 'production' for you on build, so you don't need to worry about when to set it to production.

Note: you must restart your server (e.g. run npm start again) to detect environment variable changes.