Express app Gulpfile for asset build/management with Browersify, Node Sass, Imagemin, and Browser Sync

gulpfile.js

'use strict';

const browserify = require('browserify');
const bs = require('browser-sync').create();
const buffer = require('vinyl-buffer');
const del = require('del');
const gif = require('imagemin-gifsicle');
const gulp = require('gulp');
const gutil = require('gulp-util');
const imagemin = require('gulp-imagemin');
const jpg = require('imagemin-jpegoptim');
const png = require('imagemin-optipng');
const rename = require('gulp-rename');
const sass = require('gulp-sass');
const source = require('vinyl-source-stream');
const svg = require('imagemin-svgo');

gulp.task('css', () => {
  return gulp.src('./src/css/main.scss')
    .pipe(sass({
      sourceMapEmbed: true,
      outputStyle: 'compressed'
    }).on('error', sass.logError))
    .pipe(rename({ suffix: '.min' }))
    .pipe(gulp.dest('./public/css'));
});

gulp.task('css-copy', () => {
  del('./public/css/vendor/**/*').then(() => {
    return gulp.src('./src/scss/vendor/**/*')
      .pipe(gulp.dest('./public/css/vendor'));
  });
});

gulp.task('javascript', () => {
  return browserify('./src/js/main.js', { debug: true })
    .transform('babelify', { presets: ['es2015'] })
    .transform('uglifyify')
    .bundle()
    .pipe(source('main.min.js'))
    .pipe(buffer())
    .pipe(gulp.dest('./public/js'));
});

gulp.task('javascript-copy', () => {
  del('./public/js/vendor/**/*').then(() => {
    return gulp.src('./src/js/vendor/**/*')
      .pipe(gulp.dest('./public/js/vendor'));
  });
});

// TODO run this on production builds only
gulp.task('image', () => {
  gulp.src(['./src/img/**/*'])
    .pipe(imagemin([
      jpg({ max: 50 }),
      png({ optimizationLevel: 3 }),
      gif({ optimizationLevel: 3 }),
      svg({
        minifyStyles: true,
        removeDoctype: true
      })
    ]))
    .pipe(gulp.dest('./public/img'));
});

gulp.task('image-copy', () => {
  del('./public/img/**/*').then(() => {
    return gulp.src('./src/img/**/*')
      .pipe(gulp.dest('./public/img'));
  });
});

gulp.task('reload', (done) => {
  bs.reload();
  done();
});

gulp.task('default', () => {
  bs.init({
    port: 3001,
    notify: false,
    ghostMode: true,
    proxy: 'http://localhost:3000',
  });
  gulp.watch(['src/scss/main.js', 'src/scss/lib/**/*.js'], ['css', 'reload']);
  gulp.watch(['src/scss/vendor/**/*'], ['css-copy', 'reload']);
  gulp.watch(['src/js/main.js', 'src/js/lib/**/*.js'], ['javascript', 'reload']);
  gulp.watch(['src/js/vendor/**/*'], ['javascript-copy', 'reload']);
  gulp.watch(['src/img/**/*'], ['image-copy', 'reload']);
  gulp.watch(['views/**/*'], ['reload']);
});