An example of gulpfile.js

gulpfile.js

var Promise = require('es6-promise').Promise;
var gulp = require('gulp');
var less = require('gulp-less');
var uglify = require('gulp-uglify');
var cssmin = require('gulp-clean-css');
var autoprefixer = require('gulp-autoprefixer');

// Perform tasks in given sequence
gulp.task('assets', ['css', 'js', 'img']);

// Compile less sources and copy css
gulp.task('css', function () {
	gulp.src(['less/project.less', 'less/ie.less']).pipe(less()).pipe(autoprefixer()).pipe(cssmin({ processImport: false })).pipe(gulp.dest('../../public/css/'));
	gulp.src('less/*.css').pipe(autoprefixer()).pipe(cssmin({ processImport: false })).pipe(gulp.dest('../../public/css/'));
});

// Minify and copy js
gulp.task('js', function () {
	gulp.src('js/*.js').pipe(uglify()).pipe(gulp.dest('../../public/js/'));
});

// Copy image files
gulp.task('img', function () {
	gulp.src('img/**/*').pipe(gulp.dest('../../public/img/'));
});

gulp.task('default', function () {
	gulp.watch(['js/**/*'], ['js'])
	gulp.watch(['css/**/*'], ['css']);
	gulp.watch(['img/**/*'], ['img']);
});