envlist

Micro-module (without dependency) for resolving the type of runtime environment between your application convention and another convention (like NODE_ENV).

Why?

The problem

Like the debug of Express and some Express middlewares, few modules of Node.js require to put NODE_ENV to production or development for changing the behavior of execution.

In the real world, it is common to use several environment names like local, staging, testing. Also it is common to use shortcuts and several environment names like prod, dev, stage, test, local.

The problem is that in defining NODE_ENV to local (or another alias of a development env), we do not get the full functionality of debugging of some modules.

Also in defining NODE_ENV to prod, we do not get the optimizations made to the production environment.

The solution

A simple and useful solution is to map your application environment to a conventional NODE_ENV environment. Then consolidate all 💡

Install

npm install --save envlist

or

yarn add envlist

Usage

By default envlist has preconfigured environments (of course you can replace it).

let EnvList = require('envlist');
let envList = new EnvList();

List all types of environments

console.log(envList.envs);

Output:

  local: {
    APP_ENV: 'local',
    NODE_ENV: 'development'
  },
  dev: {
    APP_ENV: 'dev',
    NODE_ENV: 'development'
  },
  stage: {
    APP_ENV: 'stage',
    NODE_ENV: 'production'
  },
  test: {
    APP_ENV: 'test',
    NODE_ENV: 'development'
  },
  prod: {
    APP_ENV: 'prod',
    NODE_ENV: 'production'
  }
}

Customize a specific environment

You can customize each environment. Example by default the value of envList.envs.test.NODE_ENV is development. If you want to change this value:

envList.envs.test.NODE_ENV = 'production';

envList.envs it's just an object (see above).

Use your own set of environments

envList.envs = {
  development: {
    APP_ENV: 'development',
    NODE_ENV: 'development'
  },
  production: {
    APP_ENV: 'production',
    NODE_ENV: 'production'
  },
  staging: {
    APP_ENV: 'staging',
    NODE_ENV: 'production'
  },
  test: {
    APP_ENV: 'test',
    NODE_ENV: 'production'
  },
  demoProd: {
    APP_ENV: 'demoProd',
    NODE_ENV: 'production'
  },
  demoDev: {
    APP_ENV: 'demoDev',
    NODE_ENV: 'development'
  }
};

Get a specific environment name

// dev
console.log(envList.envs.dev.APP_ENV);
console.log(envList.get('dev').APP_ENV);

// development
console.log(envList.envs.dev.NODE_ENV);
console.log(envList.get('dev').NODE_ENV);

// prod
console.log(envList.envs.prod.APP_ENV);
console.log(envList.get('prod').APP_ENV);

// production
console.log(envList.envs.prod.NODE_ENV);
console.log(envList.get('prod').NODE_ENV);

Get the current environment

Considers that the process was launched with the command: node APP_ENV=dev app.js

// dev
envList.env;

// dev
envList.APP_ENV;

// development
envList.NODE_ENV;

/*
  {
    APP_ENV: 'dev',
    NODE_ENV: 'development'
  }
*/
envList.getCurrent();

Ensure the current environment

It may be useful to ensure that the current environment is good and change it if it's not the desired one.

Example, ensure the dev environment:

envList.ensure('dev');

In this example, if the current environment is not equal to dev, this method change and consolidate the current environment.

Does nothing if the current environment is equal to dev.

Use your own resolver

Considers that you have installed Gulp and gulp-util and you want to support env.type:

let gutil = require('gulp-util');

envList.resolveAppEnv = function() {
  envList.env = process.env.APP_ENV || process.env.NODE_ENV || gutil.env.type;

  if(envList.env && envList.has(envList.env)) {
    return this;
  }

  throw new ReferenceError('Environment not found.');
}

Use your own consolidator

Considers that you have installed Gulp and gulp-util and you want consolidate also env.type:

let gutil = require('gulp-util');

envList.consolidate = function() {
  let current;

  if(!envList.env) {
    envList.resolveAppEnv();
  }

  if(process && process.env) {
    current = envList.getCurrent();

    process.env.APP_ENV = current.APP_ENV;
    process.env.NODE_ENV = current.NODE_ENV;
    gutil.env.type = current.NODE_ENV;
  }

  return envList;
}

If you use a framework that handle the environment based on NODE_ENV value (like Express.js), consolidate the environment before loading Express.js.

Unit tests

envlist is unit tested with Mocha and Unit.js.

Run the tests

cd node_modules/envlist && npm install && npm test

LICENSE

MIT (c) 2016, Nicolas Tallefourtane.

Author

Nicolas Talle