Adding an .env file to React Project

Question

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

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.

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 en your js file in that 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

Webpack Users

If you are using webpack, you can install and use dotenv-webpack plugin, to do that follow steps below:

Install the package

yarn add dotenv-webpack

Create a .env file

// .env
API_KEY='my secret api key'

Add it to webpack.config.js file

// webpack.config.js
const Dotenv = require('dotenv-webpack');

module.exports = {
  ...
  plugins: [
    new Dotenv()
  ]
  ...
};

Use it in your code as

process.env.API_KEY

For more information and configuration information, visit here

1. Create the .env file on your root folder

some sources prefere to use .env.development and .env.production but that's not obligatory.

2. The name of your VARIABLE -must- begin with REACT_APP_YOURVARIABLENAME

it seems that if your environment variable does not start like that so you will have problems

3. Include your variable

to include your environment variable just put on your code process.env.REACT_APP_VARIABLE

You don't have to install any external dependency

1. Install dotenv as devDependencies:

npm i --save-dev dotenv

2. Create a .env file in the root directory:

my-react-app/
|- node-modules/
|- public/
|- src/
|- .env
|- .gitignore
|- package.json
|- package.lock.json.
|- README.md

3. Update the .env file like below & REACT_APP_ is the compulsory prefix for the variable name.

REACT_APP_BASE_URL=http://localhost:8000
REACT_APP_API_KEY=YOUR-API-KEY

4. [ Optional but Good Practice ] Now you can create a configuration file to store the variables and export the variable so can use it from others file.

For example, I've create a file named base.js and update it like below:

export const BASE_URL = process.env.REACT_APP_BASE_URL;
export const API_KEY = process.env.REACT_APP_API_KEY;

5. Or you can simply just call the environment variable in your JS file in the following way:

process.env.REACT_APP_BASE_URL

Steps to use environment variables in a CREATE REACT APP

• Create a new file called .env in the root folder of the project (NOT inside src folder but one level up. Remember, it should be at the same level as package.json (THIS IS VERY IMPORTANT)

• Define your variables like so (Note that every variable you define should start with REACT_APP_)

  Example : .env file

  REACT_APP_ACCESS_KEY=8Sh9ZLwZevicWC-f_lmHvvyMu44cg3yZBU

  Note: You don't have to enclose the value in "" or ''

• Now you can use the variable in any of your components like so

  const apiKey = process.env.REACT_APP_ACCESS_KEY

  The name should match the key given in the .env file

• Now before you try this out, always remember to restart the local server. Once you run npm start it works. This step applies whenever you make changes to the .env file. We generally forget this step so it might not work.

• Optionally, check if .env entry is present in .gitignore file. If the entry of .env exists in .gitignore then your .env file will not be pushed to github(This is the reason why we use .env in the first place).