Minifying JS

Syntax#

ext An object that specifies output source and minified file extensions.
source The suffix string of the filenames that output source files ends with.
min When string: The suffix string of the filenames that output minified files ends with.
When Array: The regex expressions to be replaced with input filenames. For example: [/.(.*)-source.js$/, ‘$1.js’]
exclude Will not minify files in the dirs.
noSource Will not output the source code in the dest dirs.
ignoreFiles Will not minify files which matches the pattern.
mangle Pass false to skip mangling names.
output Pass an object if you wish to specify additional output options. The defaults are optimized for best compression.
compress Pass an object to specify custom compressor options. Pass false to skip compression completely.
preserveComments A convenience option for options.output.comments. Defaults to preserving no comments.
all Preserve all comments in code blocks
somePreserve comments that start with a bang (!) or include a Closure Compiler directive (@preserve, @license, @cc_on)
function Specify your own comment preservation function. You will be passed the current node and the current comment and are expected to return either true or false.

Remarks#

Minify JS using gulp-minify

First, Install gulp and gulp-minify to project directory locally

npm install --save-dev gulp gulp-minify

Then add following min-js task to your gulpfile.js

var gulp = require('gulp');
var minify = require('gulp-minify');

gulp.task('min-js', function() {
    return gulp.src('lib/*.js')
        .pipe(minify({
            ext: {
                min: '.min.js'
            },
            ignoreFiles: ['-min.js']
        }))
        .pipe(gulp.dest('lib'))
});

gulp.task('watch', function(){
  gulp.watch('lib/*.js', ['min-js']); 
  // Other watchers
});

gulp.task('default', ['min-js', 'watch']);

This task find all js files in lib directory, minfy it and save to lib directory with .min.js suffix. For example, after minify lib/app.js file will be created a lib/app.min.js file

Besides running as a dependency for the 'default' gulp task, this task can be run manually by typing the following command:

gulp min-js