gulpfile.js

// Load plugins
var gulp = require('gulp'),
    sass = require('gulp-ruby-sass'),
    autoprefixer = require('gulp-autoprefixer'),
    minifycss = require('gulp-minify-css'),
    jshint = require('gulp-jshint'),
    uglify = require('gulp-uglify'),
    rename = require('gulp-rename'),
    concat = require('gulp-concat'),
    notify = require('gulp-notify'),
    cache = require('gulp-cache'),
    del = require('del');

// Styles
gulp.task('styles', function() {
    return sass('assets/src/scss/app.scss')
        .pipe(autoprefixer('last 2 version', 'safari 5', 'ie 8', 'ie 9', 'opera 12.1', 'ios 6', 'android 4'))
        .pipe(gulp.dest('assets/dist/css'))
        .pipe(rename({ suffix: '.min' }))
        .pipe(minifycss())
        .pipe(gulp.dest('assets/dist/css'))
        .pipe(notify({ message: 'Styles task complete' }));
});

// Scripts
gulp.task('scripts', function() {
    return gulp.src('assets/src/js/**/*.js')
        .pipe(jshint('.jshintrc'))
        .pipe(jshint.reporter('default'))
        .pipe(concat('app.js'))
        .pipe(gulp.dest('assets/dist/js'))
        .pipe(rename({ suffix: '.min' }))
        .pipe(uglify())
        .pipe(gulp.dest('assets/dist/js'))
        .pipe(notify({ message: 'Scripts task complete' }));
});

// Clean
gulp.task('clean', function(cb) {
    del(['assets/dist/css', 'assets/dist/js'], cb)
});

// Default task
gulp.task('default', ['clean'], function() {
    gulp.start('styles', 'scripts');
});

// Watch
gulp.task('watch', function() {

    // Watch .scss files
    gulp.watch('assets/src/scss/**/*.scss', ['styles']);

    // Watch .js files
    gulp.watch('assets/src/js/**/*.js', ['scripts']);

});