Node.js - common way to pass environment variables to Node.js process (Windows, Linux, macOS, etc.)

In this article, we would like to show you common way to pass environment variables to Node.js process using any command line.

Quick solution (run in any command line):

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npx cross-env VARIABLE_NAME=VARIABLE_VALUE node script.js

Where:

• cross-env is cross platform tool that passes environment variable to indicated process,
• VARIABLE_NAME is environment variable name that we want to pass,
• VARIABLE_VALUE is environment variable value that we want to pass,
• script.js is file name that will be executed receiving the environment variable.

Note: to install cross-env tool use npm install cross-env command (locall installation).

Hint: we can use spaces and special characters in variable value by using npx cross-env VARIABLE_NAME="VARIABLE NAME" node script.js construction.

In this example, we pass ADMIN_USERNAME and ADMIN_PASSWORD environment variables into script.js script. Then we access passed variables inside script.js script using process.env property.

In your project directory you should do the following things:

1. Install dependencies using:

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npm install cross-env

Note: cross-env package will be installed locally in your project directory.

2. Create script.js file:

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console.log('Admin username: ' + process.env.ADMIN_USERNAME);

console.log('Admin password: ' + process.env.ADMIN_PASSWORD);

Run in any command line:

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npx cross-env ADMIN_USERNAME=admin ADMIN_PASSWORD=admin node script.js

Script output:

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Admin username: admin

Admin password: admin

1. Node.js - read .env file (custom solution)

2. Bash - pass environment variables to Node.js process (during command running)

3. cmd.exe - pass environment variables to Node.js process (during command running)

1. Process | Node.js v19.1.0 Documentation