gulpfile.js

/** Usage:
 * "gulp debug"         for building debug files
 * "gulp watch"         for building debug files and recreate when changed
 * "gulp build"         for building release files
 */

'use strict'
const gulp = require('gulp')
const less = require('gulp-less')
const browserify = require('browserify')
const fs = require('fs')

const TABLEMODIFY_ENTRY_SCRIPT = './src/tablemodify.js'
const TARGET_TABLEMODIFY = './dist/tablemodify.js'
const TARGET_TABLEMODIFY_MIN = './dist/tablemodify.min.js'

var debugInstance

gulp.task('default', () => null)

gulp.task('build', ['buildjs', 'less'])

gulp.task('debug', ['less', 'write_debugjs'])

gulp.task('watch', ['debug'], () => {
  gulp.watch('./src/**/*.js', ['write_debugjs'])
  gulp.watch('./src/**/*.less', ['less'])
    // Return never-resolving promise so that the task will never end
  return new Promise(() => null)
})

gulp.task('write_debugjs', () => {
  if (!debugInstance) {
    debugInstance = browserify({
      entries: [TABLEMODIFY_ENTRY_SCRIPT],
      cache: {},
      packageCache: {},
      debug: true
    }).transform('babelify', {presets: ['es2015']})
  }
    // Write the debug build to both uncompressed and minified target file
  debugInstance.bundle().pipe(fs.createWriteStream(TARGET_TABLEMODIFY))
  return debugInstance.bundle().pipe(fs.createWriteStream(TARGET_TABLEMODIFY_MIN))
})

// Task which creates minified and normal js build
gulp.task('buildjs', () => {
  getBrowserify().bundle().pipe(fs.createWriteStream(TARGET_TABLEMODIFY))
  return getBrowserify().transform('uglifyify', {global: true}).bundle().pipe(fs.createWriteStream(TARGET_TABLEMODIFY_MIN))
})

// Helper task for recompiling less files
gulp.task('less', () => {
  return gulp.src('./src/**/*.less')
        .pipe(less().on('error', err => console.log(err)))
        .pipe(gulp.dest('./dist'))
})

// ######## Helper functions #############
function getBrowserify () {
  return browserify(TABLEMODIFY_ENTRY_SCRIPT)
        .transform('babelify', {presets: ['es2015']})
}