Adding an .env file to React Project

So I'm myself new to React and I found a way to do it.

This solution does not require any extra packages.

Step 1 ReactDocs

In the above docs they mention export in Shell and other options, the one I'll attempt to explain is using .env file

1.1 create Root/.env

#.env file
REACT_APP_SECRET_NAME=secretvaluehere123

Important notes it MUST start with REACT_APP_

1.2 Access ENV variable

#App.js file or the file you need to access ENV
<p>print env secret to HTML</p>
<pre>{process.env.REACT_APP_SECRET_NAME}</pre>

handleFetchData() { // access in API call
  fetch(`https://awesome.api.io?api-key=${process.env.REACT_APP_SECRET_NAME}`)
    .then((res) => res.json())
    .then((data) => console.log(data))
}

1.3 Build Env Issue

So after I did step 1.1|2 it was not working, then I found the above issue/solution. React read/creates env when is built so you need to npm run start every time you modify the .env file so the variables get updated.

4 steps

1. npm install dotenv --save

2. Next add the following line to your app.

   require('dotenv').config()

3. Then create a .env file at the root directory of your application and add the variables to it.

// contents of .env 

REACT_APP_API_KEY = 'my-secret-api-key'

4. Finally, add .env to your .gitignore file so that Git ignores it and it never ends up on GitHub.

If you are using create-react-app then you only need step 3 and 4 but keep in mind variable needs to start with REACT_APP_ for it to work.

Reference: https://create-react-app.dev/docs/adding-custom-environment-variables/

NOTE - Need to restart application after adding variable in .env file.

Reference - https://medium.com/@thejasonfile/using-dotenv-package-to-create-environment-variables-33da4ac4ea8f

Today there is a simpler way to do that.

Just create the .env.local file in your root directory and set the variables there. In your case:

REACT_APP_API_KEY = 'my-secret-api-key'

Then you call it in your js file in the following way:

process.env.REACT_APP_API_KEY

React supports environment variables since [email protected] .You don't need external package to do that.

https://facebook.github.io/create-react-app/docs/adding-custom-environment-variables#adding-development-environment-variables-in-env

*note: I propose .env.local instead of .env because create-react-app add this file to gitignore when create the project.

Files priority:

npm start: .env.development.local, .env.development, .env.local, .env

npm run build: .env.production.local, .env.production, .env.local, .env

npm test: .env.test.local, .env.test, .env (note .env.local is missing)

More info: https://facebook.github.io/create-react-app/docs/adding-custom-environment-variables