gulpfile.js

var gulp = require( 'gulp' );
var sass = require( 'gulp-sass' );
var minifyCss = require( 'gulp-minify-css' );
var concat = require( 'gulp-concat' );
var babel = require( 'gulp-babel' );
var uglify = require( 'gulp-uglify' );
var rev = require( 'gulp-rev' );
var revReplace = require( 'gulp-rev-replace' );
var del = require( 'del' );

var paths = {
  srcScss: ['./_src/scss/**/*.scss'],
  srcScssMain: './_src/scss/application.scss',
  srcJs: ['./_src/js/**/*.js'],
  srcHtml: ['./_src/*.html'],
  srcImg: ['./_src/img/**/*'],
  disCss: './css/',
  disCssManifest: './css/rev-manifest.json',
  disJs: './js/',
  disJsManifest: './js/rev-manifest.json',
  disHtml: './',
  disImg: './img/',
  disImgManifest: './img/rev-manifest.json'
};

gulp.task( 'default', ['clean', 'scss', 'js', 'img', 'html', 'watch'] );

gulp.task( 'clean', function( done ) {
  return del([
    paths.disCss,
    paths.disJs,
    paths.disImg,
    "./index.html"
  ]);
});

gulp.task( 'scss', ['clean'], function( done ) {
  gulp.src( paths.srcScssMain )
    .pipe( sass() )
    .pipe( minifyCss() )
    .pipe( rev() )
    .pipe( gulp.dest( paths.disCss ) )
    .pipe( rev.manifest() )
    .pipe( gulp.dest( paths.disCss ) )
    .on( 'end', done );
});

gulp.task( 'js', ['clean'], function( done ) {
  gulp.src( paths.srcJs )
    .pipe( babel( { presets: ['es2015'] } ) )
    .pipe( concat( 'application.js' ) )
    .pipe( uglify() )
    .pipe( rev() )
    .pipe( gulp.dest( paths.disJs ) )
    .pipe( rev.manifest() )
    .pipe( gulp.dest( paths.disJs ) )
    .on( 'end', done );
});

gulp.task( 'html', ['clean', 'scss', 'js', 'img'], function( done ) {
  gulp.src( paths.srcHtml )
    .pipe( revReplace({
        manifest: gulp.src( paths.disCssManifest )
    }))
    .pipe( revReplace({
        manifest: gulp.src( paths.disJsManifest )
    }))
    .pipe( revReplace({
        manifest: gulp.src( paths.disImgManifest )
    }))
    .pipe( gulp.dest( paths.disHtml ) )
    .on( 'end', done );
});

gulp.task( 'img', ['clean'], function( done ) {
  gulp.src( paths.srcImg )
    .pipe( rev() )
    .pipe( gulp.dest( paths.disImg ) )
    .pipe( rev.manifest() )
    .pipe( gulp.dest( paths.disImg ) )
    .on( 'end', done );
});

gulp.task( 'watch', function() {
  gulp.watch( paths.srcScss, ['scss', 'html'] );
  gulp.watch( paths.srcJs, ['js', 'html'] );
  gulp.watch( paths.srcImg, ['img', 'html'] );
  gulp.watch( paths.srcHtml, ['html'] );
});