gulpfile.js

var gulp = require('gulp');
var concat = require('gulp-concat');
var rename = require('gulp-rename');
var shell = require('gulp-shell');
var less = require('gulp-less');
var traceur = require('gulp-traceur');
var webserver = require('gulp-webserver');

// run init tasks
gulp.task('default', ['dependencies', 'angular2', 'js', 'html', 'css', 'less']);

// run development task
gulp.task('dev', ['watch', 'serve']);

// serve the build dir
gulp.task('serve', function() {
  gulp.src('build')
    .pipe(webserver({
      host: '0.0.0.0',
      open: true
    }));
});

// watch for changes and run the relevant task
gulp.task('watch', function() {
  gulp.watch('src/**/*.js', ['js']);
  gulp.watch('src/**/*.html', ['html']);
  gulp.watch('src/**/*.css', ['css']);
  gulp.watch('src/**/*.less', ['less']);
});

// move dependencies into build dir
gulp.task('dependencies', function() {
  return gulp.src([
      'node_modules/angular2/node_modules/rx/dist/rx.all.js',
      'node_modules/angular2/node_modules/traceur/bin/traceur.js',
      'node_modules/angular2/node_modules/traceur/bin/traceur-runtime.js',
      'node_modules/angular2/node_modules/zone.js/zone.js',
      'node_modules/es6-module-loader/dist/es6-module-loader.js',
      'node_modules/es6-module-loader/dist/es6-module-loader.js.map',
      'node_modules/systemjs/dist/system.js',
      'node_modules/systemjs/dist/system.js.map'
    ])
    .pipe(gulp.dest('build/lib'));
});

// tanspile, concat & move angular
gulp.task('angular2', function() {
  return gulp.src([
      traceur.RUNTIME_PATH,
      'node_modules/angular2/es6/prod/*.es6',
      'node_modules/angular2/es6/prod/src/**/*.es6'
    ], {
      base: 'node_modules/angular2/es6/prod'
    })
    .pipe(rename(function(path) {
      path.dirname = 'angular2/' + path.dirname;
      path.extname = '';
    }))
    .pipe(traceur({
      modules: 'instantiate',
      moduleName: true
    }))
    .pipe(concat('angular2.js'))
    .pipe(gulp.dest('build/lib'));
});

// transpile & move js
gulp.task('js', function() {
  return gulp.src('src/**/*.js')
    .pipe(rename({
      extname: ''
    }))
    .pipe(traceur({
      modules: 'instantiate',
      moduleName: true,
      annotations: true,
      types: true
    }))
    .pipe(rename({
      extname: '.js'
    }))
    .pipe(gulp.dest('build'));
});

// move html
gulp.task('html', function() {
  return gulp.src('src/**/*.html')
    .pipe(gulp.dest('build'))
});

// move css
gulp.task('css', function() {
  return gulp.src('src/**/*.css')
    .pipe(gulp.dest('build/css'))
});

// less
gulp.task('less', function() {
    return gulp.src('./src/less/main.less')
        .pipe(less())
        .pipe(gulp.dest('build/css/'))
});