Gulpfile for Rails with livereload

Gulpfile.js

'use strict';

var gulp = require('gulp');
var sass = require('gulp-sass');
var livereload = require('gulp-livereload');
var babel = require('babelify');
var browserify = require('browserify');
var source = require('vinyl-source-stream');
var exec = require('child_process').exec;

gulp.task('sass', function () {
  gulp.src('./app/assets/stylesheets/application.scss')
    .pipe(sass().on('error', sass.logError))
    .pipe(gulp.dest('./public/assets/stylesheets'))
    .pipe(livereload());
});

gulp.task('js', function() {
  browserify('./app/assets/javascripts/application.js')
    .transform(babel, {presets: ['es2015']})
    .bundle()
    .pipe(source('application.js'))
    .pipe(gulp.dest('./public/assets/javascripts'))
    .pipe(livereload());
});

gulp.task('watch', function(cb) {
  exec('bin/rails s', function(err, stdout, stderr) {
    console.log(stdout);
    console.log(stderr);
    cb(err);
  });
  livereload.listen();
  gulp.watch('./app/assets/stylesheets/**/*.scss', ['sass']);
  gulp.watch('./app/assets/javascripts/**/*.js', ['js']);
  gulp.watch('./app/views/**/*.html.erb').on('change', function(file) {
    livereload.changed(file.path);
  });
});

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

This is a simple Gulpfile I create to get some kind of livereloading functionality in a Rails app that doesn't use Sprockets. It relies on a way to have a livereload plugin in your app, gem 'rack-livereload' for instance.