gulpfile.js for browserify + backbone.js + ractive.js, with watchify

gulpfile.js

var path        = require("path");

var gulp        = require("gulp");
var less        = require("gulp-less");
var notify      = require("gulp-notify");
var rename      = require("gulp-rename");
var minifyCSS   = require("gulp-minify-css");
var uglify      = require("gulp-uglifyjs");
var livereload  = require("gulp-livereload");
var source      = require("vinyl-source-stream");

var browserify  = require("browserify");
var watchify    = require("watchify");

var ractivate   = require("ractivate");


function ErrorHandler(err) {
    var args = Array.prototype.slice.call(arguments);

    // Send error to notification center with gulp-notify
    notify.onError({
        title: "Compile Error",
        message: "<%= error.message %>"
    }).apply(this, args);
    
    // Print stacktrace for Error
    console.log(err.stack)

    // Keep gulp from hanging on this task
    this.emit("end");
}


function Bundler (factory) {
    this.bundle = factory("./app/assets/js/app.js")
        .transform({extensions: [".mustache"]}, ractivate)
}

Bundler.prototype.run = function () {
    return this.bundle
        .bundle({debug: true})
        .on("error", ErrorHandler)
        .pipe(source("app.js"))
        .pipe(gulp.dest("./public/assets/js"))
}

Bundler.prototype.on = function () {
    return this.bundle.on.apply(this.bundle, arguments)
}


/********************************************************************
 *
 * Tasks
 *
 ********************************************************************/


gulp.task("browserify", function(){
    var bundler = new Bundler(browserify)
    bundler.run()
});


gulp.task("watchify", function(){
    var bundler = new Bundler(watchify)
    bundler.on("update", function(){
        return bundler.run()
    })
    return bundler.run()
});


gulp.task("uglify", function(){
    gulp.src("./public/assets/js/app.js")
        .pipe(uglify("app.min.js", {
            outSourceMap: true
        }))
        .pipe(gulp.dest("./public/assets/js"))
});


gulp.task("less", function(){
    gulp.src("./app/assets/less/app.less")
        .on("error", ErrorHandler)
        .pipe(less({
            paths: [ path.join(__dirname, "app", "assets", "less", "includes") ]
        }))
        .pipe(gulp.dest("./public/assets/css"))
        .pipe(minifyCSS())
        .pipe(rename({suffix: ".min"}))
        .pipe(gulp.dest("./public/assets/css"))
});


gulp.task("watch", ["watchify"], function(){
    gulp.watch("./public/assets/js/app.js", ["uglify"]);
    gulp.watch("./app/assets/less/**", ["less"]);
});

gulp.task("build", ["browserify", "uglify", "less"]);