envg

Configure environment variables with Node.js

Getting started

1. npm i envg
2. prepare env/example.js file like that

module.exports = {
  HOGE: 'hogehoge',
  FUGA: 'fugafuga',
  NODE_ENV: 'example',
};

3. Configure npm-scripts of your package.json like that

"scripts": {
  "start": "envg example <your_command>"
}

4. You can use environment variables defined by env/example.js in any your command!

# with process.env
$ npx envg example node -e "console.log(process.env.HOGE)"
>> hogehoge

# with reuire('envg')
$ cat print.js
const { env } = require('envg');
cnosole.log(env.HOGE);

$ npx envg example node print.js
>> hogehoge

# with non-js file
$ cat print.sh
echo $HOGE

$ npx envg sh print.sh
>> hogehoge

Advanced usage

Overwrite environment variable

env/<env_name>.js file can be overwritten by environment variable, these values works as default. For example, if you have such a env/example.js file:

module.exports = {
  HOGE: 'hogehoge',
  FUGA: 'fugafuga',
  NODE_ENV: 'example',
};

You can overwrite these environment keys (HOGE, FUGA, NODE_ENV):

$ npx envg example node -e "console.log(process.env.HOGE)"
>> hogehoge

$ HOGE=overwritten npx envg example node -e "console.log(process.env.HOGE)"
>> overwritten

You don't need to write HOGE: process.env.HOGE || 'hogehoge' or something in env file.

Define environment variable with non-default value

You may require environment variable which has non-default value but used in application. For example, you have secret token which is passed in environment variable, but not exposed in source code.

In that case, you can configure such a variable with undefined value, like that (env/secret.js):

module.exports = {
  SECRET_VALUE: undefined,
};

This SECRET_VALUE should be passed as environment variable, otherwise envg will be failed for preventing your command runs with non SECRET_VALUE value. You don't require your own validation logic for process.env.SECRET_VALUE in that case.

# it will be failed before `npm start`
$ npx envg secret npm start

# it will work well
$ SECRET_VALUE=XXX npx envg secret npm start

envg