nenv

Table of Contents
=================

* Node Environment (NODE_ENV)
* Install
* Usage
* API
* [env([value])](#envvalue)
* env.value
* env.valid
* env.defined
* env.get()
* env.set(val)
* env.keys
* env.map
* env.jsonify()
* nenv.defaults
* nenv.cache
* nenv.get
* nenv.set
* Environments
* Getter
* Example
* Developer
* Test
* Cover
* Lint
* Readme
* License

Node Environment (NODE_ENV)
===========================

.

Utility for mananging node development environments.

Install

``
npm i nenv --save
`

Usage

`javascript
var env = require('nenv')();
if(!env.defined) {
// do something when no environment was specified
// maybe: env.set(env.DEVEL) or whichever default you want
}else if(!env.valid) {
// do something when the specified environment is invalid
// and the debug flag is not set
}else if(env.test && !env.debug) {
// do something for test environment
}
`

API

`javascript
function nenv([environments, get, set])
`

* environments: Array or object of custom environments, if not specified the defaults are used.
* get: A custom function for getting the environment value (optional).
* set: A custom function for setting the environment value (optional).
* dbg: A string for the debug flag environment variable, default is DEBUG.

The returned query object maintains a special debug property which is a boolean indicating whether the DEBUG environment variable has been set, if this conflicts with an environment name either change the environments or dbg options.

The query object is maintained in a cache and will be returned on subsequenct calls which is typically desirable, if you need a fresh query delete nenv.cache.

$3

Determines if an environment value is valid. Returns false if the supplied value is invalid or the string key for the environment if the value is a known environment alias.

If no value is supplied then env.value is used which allows testing whether the default value is valid by calling with no arguments.

$3

The value returned from get() when nenv() was called, the initial environment value.

$3

Boolean that determines whether env.value is a recognised environment.

$3

Determines whether an initial value (env.value) was defined.

$3

Get the current value of the environment, the default implementation returns process.env.NODE_ENV.

$3

Set the current value of the environment, the default implementation returns false if the supplied value is not a known environment alias otherwise a function that may be called to revert to the previous value.

$3

Array of environment keys.

$3

Map of environment keys to arrays of string aliases for the environment.

$3

Return an object suitable for passing to JSON.stringify.

$3

Default values to use.

`javascript
['test', 'devel', 'stage', 'production'];
`

$3

A cache created the first time nenv() was invoked. Typically you would always want to share the same environment query:

`javascript
var nenv = require('nenv')
, env = nenv()
, newenv = nenv()
// bypass cache and get a new query function using defaults
, altenv = nenv(true);
console.log(env === newenv);
console.log(env === altenv);
`

You can bypass the cached instance by passing arguments to nenv() or alternatively you could delete nenv.cache to force a new query to be created.

$3

Default get function.

$3

Default set function.

Environments

Pass an object or array to define your available environments. Passing an object allows specifying multiple keys as aliases for the environment, useful to alias shortcuts for longer environment identifiers.

`javascript
var nenv = require('nenv');
console.dir(nenv(['test', 'dev', 'stage']));
console.dir(nenv({production: ['production', 'pro'], dev: 'dev', test: 'test'}));
`

Getter

Use a fallback value by supplying a get function:

`javascript
var nenv = require('nenv');
function fallback() {
return process.env.NODE_ENV || this.PRODUCTION;
}
var env = nenv(fallback);
console.dir(env);
`

Or apply override logic to prefer another variable:

`javascript
var nenv = require('nenv');
function override() {
return process.env.ENV || process.env.NODE_ENV;
}
var env = nenv(override);
console.dir(env);
`

Example

See defaults.js.

`javascript
var env = require('./')()
, str = JSON.stringify(env.jsonify(), undefined, 2);
process.stdout.write(str);
`

Executed with NODE_ENV=devel, yields:

`json
{
"TEST": "test",
"DEVEL": "devel",
"STAGE": "stage",
"PRODUCTION": "production",
"debug": false,
"value": "devel",
"current": "devel",
"valid": true,
"defined": true,
"map": {
"test": [
"test"
],
"devel": [
"devel"
],
"stage": [
"stage"
],
"production": [
"production"
]
},
"keys": [
"test",
"devel",
"stage",
"production"
],
"test": false,
"devel": true,
"stage": false,
"production": false
}
`

Developer

$3

Run the test specifications:

`
npm test
`

$3

Run the test specifications and generate code coverage:

`
npm run cover
`

$3

Run the source tree through jshint and jscs:

`
npm run lint
`

$3

Generate the project readme file (requires mdp):

`
npm run readme
``

License

Everything is MIT. Read the license if you feel inclined.

Generated by mdp(1).

[node]: http://nodejs.org
[npm]: http://www.npmjs.org
[mdp]: https://github.com/tmpfs/mdp
[jshint]: http://jshint.com
[jscs]: http://jscs.info