zertosh / stream-if-env

Create conditional object streams based on NODE_ENV

stream-if-env

Create conditional object streams based on NODE_ENV. If the environment doesn't match, the stream function is not called, and a through stream is returned instead. If the environment matches, then the passed function is called with all the remaining arguments. Optionally, if a function is not passed, a boolean is returned based on a match of the environment.

Usage

• when('development', streamFn, [arg1, arg2, ...])

  If NODE_ENV is equal to development, when returns the value of calling streamFn with arguments arg1, arg2, etc. If not, then a through stream is returned.

• unless('development', streamFn, [arg1, arg2, ...])

  If NODE_ENV is not equal to development, unless returns the value of calling streamFn with arguments arg1, arg2, etc. If not, then a through stream is returned.

• when(NODE_ENV)/unless(NODE_ENV)

  If either when or unless are only called with an environment to test, then the boolean result of the environment match is returned.

Examples

The examples are based on gulp, but any stream will do.

var gulp = require('gulp');
var uglify = require('uglify');

var when = require('stream-if-env').when;

gulp.task('scripts', function() {
  return gulp.src('app/*.js')
    .pipe(when('production', uglify, {preserveComments: true}))
    .pipe(gulp.dest('public'));
});

var unless = require('stream-if-env').unless;
if (unless('development')) {
  console.log('NODE_ENV is not "development"');
}

Tip

Calling when and unless with the environment each time is probably not necesarry since you're most likely testing for production or development. So, create a partial function instead.

var ifProd = require('stream-if-env').when.bind(null, 'production');
//..
  return gulp.src('app/*.js')
    .pipe(ifProd(uglify, {preserveComments: true}))
    .pipe(gulp.dest('public'));
//...

var notDev = require('stream-if-env').unless.bind(null, 'development');
if (notDev()) {
  console.log('NODE_ENV is not "development"');
}