Get and typecast environment variables.


Helper to get and typecast environment variables. This is especially useful if you are building Twelve-Factor-Apps where all configuration is stored in the environment.

npm install getenv

Set environment variables:

export HTTP_HOST="localhost"
export HTTP_PORT=8080
export HTTP_START=true
export AB_TEST_RATIO=0.5
export KEYWORDS="sports,business"
export PRIMES="2,3,5,7"

Get and use them:

var getenv = require('getenv');
var host = getenv('HTTP_HOST'); // same as getenv.string('HTTP_HOST'); 
var port ='HTTP_PORT');
var start = getenv.bool('HTTP_START');
if (start === true) {
  // var server = http.createServer(); 
  // server.listen(port, host); 
var abTestRatio = getenv.float('AB_TEST_RATIO');
if (Math.random() < abTestRatio) {
  // test A 
} else {
  // test B 
var keywords = getenv.array('KEYWORDS');
keywords.forEach(function(keyword) {
  // console.log(keyword); 
var primes = getenv.array('PRIMES', 'int');
primes.forEach(function(prime) {
  // console.log(prime, typeof prime); 

All methods accept a fallback value that will be returned if the requested environment variable is not set. If the fallback value is omitted and if the requested environment variable does not exist, an exception is thrown.

Alias for env.string(name, [fallback]).

Return as string.

Return as integer number.

Return as float number.

Return as boolean.

Split value of the environment variable at each comma and return the resulting array where each value has been typecast according to the type parameter. An array can be provided as fallback.

Return a list of environment variables based on a spec:

var config = getenv.multi({
  foo: "FOO", // throws if FOO doesn't exist 
  bar: ["BAR", "defaultval"], // set a default value 
  baz: ["BAZ", "defaultval", "string"], // parse into type 
  quux: ["QUUX", undefined, "integer"] // parse & throw 

Return a parsed URL as per Node's require("url").parse. N.B url doesn't validate URLs, so be sure it includes a protocol or you'll get deeply weird results.

var serviceUrl = getenv.url('SERVICE_URL');
serviceUrl.port; // parsed port number 

Disallows fallbacks in environments where you don't want to rely on brittle development defaults (e.g production, integration testing). For example, to disable fallbacks if we indicate production via NODE_ENV:

if (process.env.NODE_ENV === 'production') {
  • Add getenv.url() support.
  • Add getenv.disableFallbacks() support.
  • Add getenv.multi() support.
  • Rename git repository
  • Initial release

This module is licensed under the MIT license.