gulpfile.babel.js

import gulp from 'gulp'
import babel from 'gulp-babel'
import rimraf from 'gulp-rimraf'

const paths = {
  in: {
    js: 'lib/*.js',
    assets: 'lib/assets/*'
  },
  out: {
    js: 'dist',
    assets: 'dist/assets'
  }
}

gulp.task('transpile', () => {
  return gulp.src(paths.in.js)
  .pipe(babel())
  .pipe(gulp.dest(paths.out.js))
})

gulp.task('assets', () => {
  return gulp.src(paths.in.assets)
  .pipe(gulp.dest(paths.out.assets))
})

gulp.task('clean', () => {
  return gulp.src(paths.out.js, {
    read: false
  })
  .pipe(rimraf())
})

gulp.task('default', ['transpile', 'assets'])