Bootstrap Gulp Workflow

gulpfile.js

var gulp = require('gulp'),
    autoprefixer = require('gulp-autoprefixer'),
    browserSync = require('browser-sync').create(),
    concat = require("gulp-concat"),
    imagemin = require('gulp-imagemin'),
    sass = require('gulp-sass'),
    sourcemaps = require('gulp-sourcemaps'),
    browserify = require('browserify'),
    babelify = require('babelify'),
    source = require('vinyl-source-stream'),
    buffer = require('vinyl-buffer'),
    uglify = require('gulp-uglify'),

    config = {
        src: 'src/',
        dest: './',
        url: '%PROXY_URL%',
    };


// -----------------------
//          TASKS
// -----------------------

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

gulp.task('build', ['images','scss', 'js']);

gulp.task('images', function () {
    return gulp.src(config.src+'img/**/*')
        .pipe(imagemin())
        .pipe(gulp.dest(config.dest+'img'))
        .pipe(browserSync.stream());
});


gulp.task('js', function() {
    return browserify('./src/js/main.js')
        .transform(babelify, { "presets": ["es2015"] })
        .bundle()
        .on('error', function(e){
            console.log(e.message);
            this.emit('end');
        })
        .pipe(source('main.min.js'))
        .pipe(buffer()).pipe(uglify())
        .pipe(gulp.dest('js'))
        .pipe(browserSync.stream());
});

gulp.task('scss', function () {
    return gulp.src(config.src+'scss/**/*.scss')
        .pipe(sourcemaps.init())
        .pipe(
            sass({outputStyle: 'compressed'})
            .on('error', sass.logError))
        .pipe(autoprefixer({
            browsers: ['>1%', 'last 2 versions'],
            cascade: false
        }))
        .pipe(sourcemaps.write('.'))
        .pipe(gulp.dest(config.dest+'css'))
        .pipe(browserSync.stream());
});

gulp.task('watch', function () {
    browserSync.init({
        // server: { baseDir: config.dest },
        proxy: config.url
    });
    gulp.watch(config.src+'scss/**/*.scss', ['scss']);
    gulp.watch(config.src+'img/**/*', ['images']);
    gulp.watch(config.src+'js/**/*', ['js']);
    gulp.watch(config.dest+'**/*.{html,php,inc}').on('change', browserSync.reload);
});

shell

npm init && npm install --save-dev gulp autoprefixer gulp-autoprefixer browser-sync gulp-concat gulp-imagemin gulp-sass gulp-sourcemaps browserify babelify babel-preset-es2015 vinyl-source-stream vinyl-buffer gulp-uglify