Gulpfile for Ionic with error handling. Babel(es2015), Sass, and Jade.

gulpfile.js

var gulp      = require('gulp');
var gutil     = require('gulp-util');
var bower     = require('bower');
var concat    = require('gulp-concat');
var sass      = require('gulp-sass');
var minifyCss = require('gulp-minify-css');
var rename    = require('gulp-rename');
var sh        = require('shelljs');
var jade      = require('jade');
var gulpJade  = require('gulp-jade');
var babel     = require('gulp-babel');
var del       = require('del');
var gulpCopy  = require('gulp-copy');
var plumber   = require('gulp-plumber');
var header    = require('gulp-header');

var paths = {
  sass: ['./public/scss/**/*.scss'],
  jade: ['./public/jade/**/*.jade'],
  es6 : ['./public/es6/**/*.js'],
  img : ['./public/img/**/*']
};

var onError = function (err) {
  gutil.beep();
  console.log(err);
};

var headerMessage = 'This is a compiled file. Do Not Edit. The source file is in ./public';

gulp.task('default', ['build', 'watch']);

gulp.task('build', ['copy', 'sass', 'jade', 'es6']);

gulp.task('copy',['clean'], function() {
  return gulp.src(paths.img)
    .pipe(plumber(onError))
    .pipe(gulpCopy('./www/', {prefix: 1}));
});


gulp.task('clean', function () {
  del(['./www/img/**/*']);
});

gulp.task('es6', () => {
  return gulp.src(paths.es6)
    .pipe(plumber(onError))
    .pipe(babel({
      plugins: ['transform-es2015-arrow-functions',
                'transform-es2015-template-literals',
                'transform-es2015-parameters',
                'transform-es2015-for-of'
               ]
    }))
    .pipe(header(`// ${headerMessage}\n\n`))
    .pipe(gulp.dest('./www/js'));
});

gulp.task('jade', function (done) {
  gulp.src(paths.jade)
    .pipe(plumber(onError))
    .pipe(gulpJade({
      jade: jade,
      pretty: true
    }))
    .pipe(header(`<!-- ${headerMessage} -->\n\n`))
    .pipe(gulp.dest('./www/'))
    .on('end', done);
});


gulp.task('sass', function(done) {
  gulp.src(paths.sass)
    .pipe(plumber(onError))
    .pipe(sass())
    .on('error', sass.logError)
    .pipe(header(`/* ${headerMessage} */\n\n`))
    .pipe(gulp.dest('./www/css/'))
    .pipe(minifyCss({
      keepSpecialComments: 0
    }))
    .pipe(rename({ extname: '.min.css' }))
    .pipe(gulp.dest('./www/css/'))
    .on('end', done);
});

gulp.task('watch', function() {
  gulp.watch(paths.sass, ['sass']);
  gulp.watch(paths.jade, ['jade']);
  gulp.watch(paths.es6,  ['es6']);
  gulp.watch(paths.img,  ['copy']);
});

gulp.task('install', ['git-check'], function() {
  return bower.commands.install()
    .on('log', function(data) {
      gutil.log('bower', gutil.colors.cyan(data.id), data.message);
    });
});

gulp.task('git-check', function(done) {
  if (!sh.which('git')) {
    console.log(
      '  ' + gutil.colors.red('Git is not installed.'),
      '\n  Git, the version control system, is required to download Ionic.',
      '\n  Download git here:', gutil.colors.cyan('http://git-scm.com/downloads') + '.',
      '\n  Once git is installed, run \'' + gutil.colors.cyan('gulp install') + '\' again.'
    );
    process.exit(1);
  }
  done();
});

Don't forget to install your dependencies
npm install --save-dev gulp jade gulp-jade gulp-babel del gulp-copy gulp-plumber gulp-header

Create a public folder in the root of the project and with the subdirectories sass, sade, es6, and img for all of your precompiled code.