Run npm scripts on Windows that set (common) environment variables.

Problem

If you're on Windows, you've probably encountered an error like:

'NODE_ENV' is not recognized as an internal or external command, operable program or batch file.

which comes from an npm script in your project set up like this:

"scripts": {

  "build": "NODE_ENV=production babel src --out-dir dist"

}

Setting NODE_ENV=production before command babel doesn't work on Windows.

You might use cross-env but that involves changing your npm scripts and getting Mac/*nix users onboard.

Solution

win-node-env creates executables like NODE_ENV.cmd that sets the NODE_ENV environment variable and runs the rest of the command.

Install

You may install it globally:

npm install -g win-node-env

Or you may include it in your project's or your library's optional dependencies:

npm install --save-optional win-node-env

It won't install on any other OS than Windows.

Usage

Just install it and run your npm script commands, it should automatically make them work.

NODE_ENV=production cmd /c echo %NODE_ENV%

should output:

production

Apart from NODE_ENV there's a few more commonly used env vars:

• DEBUG
• ENV
• PORT
• NODE_OPTIONS

You can also use multiple env vars, as long as the first one is one of the above

NODE_ENV=production MY_VAR=something cmd /c echo %MY_VAR%

Bonus

It now also supports ; character!

ENV=1 command; command

Although any &&, ||, and & might break it.

ENV=1 command && command ; command

^^^^^^^^^^^^^    ^^^^^^^^^^^^^^^^^

processed by     not processed by

win-node-env     win-node-env

Tip: to add even more custom variables

If you'd like to add even more custom variable(s) (that you can specify as first) you can do so like this.

Suppose you want to add MY_VAR, place a file named MY_VAR.cmd where it can be accessed by your command prompt. (when you enter a command in your command prompt, say MY_VAR, it looks for a file with the name MY_VAR.cmd in a list of pre-defined paths. This list of pre-defined paths resides in the environment variable PATH. You can edit it to include the path containing your MY_VAR.cmd file)

Make sure this module is installed globally.

Then simply put the following code in this file:

• MY_VAR.cmd

  @ECHO OFF

  SET NODE_PATH=%APPDATA%\npm\node_modules

  node -e "require('win-node-env')('%~n0')" X %*

  • NODE_PATH tells require where to look for.

  • %APPDATA%\npm\node_modules is generally where your globally installed modules live

  • %~n0 expands to the current file's name (without extension), i.e. 'MY_VAR'

  • X is a dummy argument that's just needed for some reason

  • %* expands all the arguments passed to the batch file, and passes them on to this module

You can use the same contents of this file for any other variable names as well, i.e. just copy this file and change the filename.