gulpfile.js

var path = require('path');

var gulp = require('gulp');
var babel = require('gulp-babel');
var cleanCSS = require('gulp-clean-css');
var concat = require('gulp-concat');
var del = require('del');
var dotPreparse = require('gulp-dot-preparse');
var header = require('gulp-header');
var sass = require('gulp-sass');

const clientSourceFolder = path.join('src', 'client');
const clientDistFolder = path.join('dist', 'client');
const jsDestinationFolder = path.join(clientDistFolder, 'js');

const mainHtmlSrc = path.join(clientSourceFolder, 'index.html');
const fontsSrc = path.join(clientSourceFolder, 'fonts', '**', '*');
const imagesSrc = path.join(clientSourceFolder, 'images', '**', '*');
const extJsSrc = path.join(clientSourceFolder, 'js', 'ext', '**', '*');
const jsToTranspile = path.join(clientSourceFolder, 'js', '*.js');
const templatesLocation = path.join(clientSourceFolder, 'templates', '**', '*.jst');

gulp.task('sass', function () {
    const mainSassFile = path.join(clientSourceFolder, 'scss', 'app.scss');
    const cssDestinationFolder = path.join(clientDistFolder, 'css');
    return gulp.src(mainSassFile)
        .pipe(sass())
        .pipe(cleanCSS({ compatibility: 'ie9' }))
        .pipe(gulp.dest(cssDestinationFolder));
});

gulp.task('babel', function () {
    return gulp.src(jsToTranspile)
        .pipe(babel({
            presets: ['es2015']
        }))
        .pipe(gulp.dest(jsDestinationFolder));
});

gulp.task('templates', function () {
    return gulp.src(templatesLocation)
        .pipe(dotPreparse({
            root: path.join(clientSourceFolder, 'templates'),
            global: 'render',
            templateSettings: {
                varname: 'model'
            }
        }))
        .pipe(concat('templates.js'))
        .pipe(header('window.render={};'))
        .pipe(gulp.dest(jsDestinationFolder));
});

gulp.task('copy', function () {
    gulp.src(mainHtmlSrc).pipe(gulp.dest(clientDistFolder));

    const fontsDist = path.join(clientDistFolder, 'fonts');
    gulp.src(fontsSrc).pipe(gulp.dest(fontsDist));

    const extJsDist = path.join(clientDistFolder, 'js', 'ext');
    gulp.src(extJsSrc).pipe(gulp.dest(extJsDist));

    // To delete after development
    const imagesDist = path.join(clientDistFolder, 'images');
    gulp.src(imagesSrc).pipe(gulp.dest(imagesDist));

    return;
});

gulp.task('watch:client', function () {
    gulp.watch(mainHtmlSrc, ['copy']);
    gulp.watch(fontsSrc, ['copy']);
    gulp.watch(imagesSrc, ['copy']);
    gulp.watch(extJsSrc, ['copy']);
    gulp.watch(path.join(clientSourceFolder, 'scss', '**', '*'), ['sass']);
    gulp.watch(jsToTranspile, ['babel']);
    gulp.watch(templatesLocation, ['templates']);
});

gulp.task('clean', function () {
    return del('dist/**/*', { force: true });
});

gulp.task('build:client', ['copy', 'sass', 'babel', 'templates']);

gulp.task('build', ['clean'], function () {
    gulp.start('build:client');
});

gulp.task('build:watch', ['build'], function () {
    gulp.start('watch:client');
});