gulp

// --- INIT
var gulp = require('gulp'),  
    less = require('gulp-less'), // compiles less to CSS
    minify = require('gulp-minify-css'), // minifies CSS
    concat = require('gulp-concat'),
    uglify = require('gulp-uglify'), // minifies JS
    rename = require('gulp-rename'),
    browserSync = require('browser-sync');

// Start the server
gulp.task('browser-sync', function() {
    browserSync({
        server: {
            baseDir: "./"
        },
        open: false,
    });
});

var paths = {  
    'dev': {
        'less': './dev/less/',
        'js': './dev/js/',
        'vendor': './dev/vendor/'
    },
    'assets': {
        'css': './assets/css/',
        'js': './assets/js/',
        'vendor': './bower_vendor/'
    }
};

function swallowError(error) { 
    console.log(error.toString());
    this.emit('end'); 
}

// --- TASKS
gulp.task('frontend.css', function() {  
  // place code for your default task here
  return gulp.src(paths.dev.less+'frontend.less') // get file
    .pipe(less()).on('error', swallowError)
    .pipe(gulp.dest(paths.assets.css)) // output: frontend.css
    .pipe(minify({keepSpecialComments:0}))
    .pipe(rename({suffix: '.min'}))
    .pipe(gulp.dest(paths.assets.css)) // output: frontend.min.css
    .pipe(browserSync.reload({stream:true})); // reload browser
});

gulp.task('frontend.js', function() {  
  return gulp.src([
      paths.assets.vendor+'jquery/dist/jquery.js',
      paths.assets.vendor+'bootstrap/dist/js/bootstrap.js',
      paths.dev.js+'frontend.js'
    ])
    .pipe(concat('frontend.min.js'))
    .pipe(uglify()).on('error', swallowError)
    .pipe(gulp.dest(paths.assets.js))
    .pipe(browserSync.reload({stream:true})); // reload browser
});

// --- WATCH
//Rerun the task when a file changes
gulp.task('watch', ['browser-sync'], function() {  
  gulp.watch(paths.dev.less + '*.less', ['frontend.css', browserSync.reload]);
  gulp.watch(paths.dev.js + '*.js', ['frontend.js', browserSync.reload]);
  gulp.watch("*.html", browserSync.reload);
});