process.env#

process.env#

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• <Object>

The process.env property returns an object containing the user environment. See environ(7).

An example of this object looks like:

{
  TERM: 'xterm-256color',
  SHELL: '/usr/local/bin/bash',
  USER: 'maciej',
  PATH: '~/.bin/:/usr/bin:/bin:/usr/sbin:/sbin:/usr/local/bin',
  PWD: '/Users/maciej',
  EDITOR: 'vim',
  SHLVL: '1',
  HOME: '/Users/maciej',
  LOGNAME: 'maciej',
  _: '/usr/local/bin/node'
} COPY

It is possible to modify this object, but such modifications will not be reflected outside the Node.js process, or (unless explicitly requested) to other Worker threads. In other words, the following example would not work:

node -e 'process.env.foo = "bar"' && echo $foo COPY

While the following will:

const { env } = require('node:process');

env.foo = 'bar';
console.log(env.foo);COPY

Assigning a property on process.env will implicitly convert the value to a string. This behavior is deprecated. Future versions of Node.js may throw an error when the value is not a string, number, or boolean.

const { env } = require('node:process');

env.test = null;
console.log(env.test);
// => 'null'
env.test = undefined;
console.log(env.test);
// => 'undefined'COPY

Use delete to delete a property from process.env.

const { env } = require('node:process');

env.TEST = 1;
delete env.TEST;
console.log(env.TEST);
// => undefinedCOPY

On Windows operating systems, environment variables are case-insensitive.

const { env } = require('node:process');

env.TEST = 1;
console.log(env.test);
// => 1COPY

Unless explicitly specified when creating a Worker instance, each Worker thread has its own copy of process.env, based on its parent thread's process.env, or whatever was specified as the env option to the Worker constructor. Changes to process.env will not be visible across Worker threads, and only the main thread can make changes that are visible to the operating system or to native add-ons. On Windows, a copy of process.env on a Worker instance operates in a case-sensitive manner unlike the main thread.