gulpfile.js

var gulp = require("gulp");
var buffer = require("vinyl-buffer");
var source = require("vinyl-source-stream");
var sourcemaps = require("gulp-sourcemaps");

var sass = require("gulp-ruby-sass");
var rename = require("gulp-rename");
var autoprefixer = require("gulp-autoprefixer");
var minifycss = require("gulp-minify-css");

var browserify = require("browserify");

gulp.task("sass", function () {
	return sass("style/*.scss")
		.on("error", sass.logError)
		.pipe(autoprefixer({
			browsers: ["last 10 versions", "> 5%"],
			cascade: false
		}))
		.pipe(minifycss())
		.pipe(rename("style/app.css"))
		.pipe(gulp.dest(""));
});

gulp.task("js", function() {
	var bundler = browserify("js/src/app-base.js", {
			debug: true
		})
		.transform("babelify", {
			presets: ["es2015", "stage-0"]
		});

	return bundler.bundle()
		.on("error", function(err) {
			console.error(err);
			this.emit("end");
		})
		.pipe(source("app.js"))
		.pipe(buffer())
		.pipe(sourcemaps.init({ loadMaps: true }))
		.pipe(sourcemaps.write("./"))
		.pipe(gulp.dest("js/dist/"));
});

gulp.task("default", function(){
	gulp.watch("style/*.scss", ["sass"]);
	gulp.watch("js/src/*.js", ["js"]);
});