babel transform that unlinks deleted/renamed files

gulpfile.babel.js

import gulp from 'gulp'
import babel from 'gulp-babel'
import combiner from 'stream-combiner2'
import sourcemaps from 'gulp-sourcemaps'
import watch from 'gulp-watch'
import gulpif from 'gulp-if'
import del from 'del'
import vinylPaths from 'vinyl-paths'

gulp.task('default', function () {
  const babelTransform = combiner.obj([
    sourcemaps.init(),
    babel({
      stage: 1,
      blacklist: ['regenerator'],
      optional: ['runtime', 'bluebirdCoroutines']
    }),
    sourcemaps.write('.')
  ])

  const unlinkEvent = ({ event }) => event === 'unlink' || event === 'unlinkDir'

  return gulp.src('src/**/*')
    .pipe(watch('src/**/*'))
    .pipe(gulpif(/\.jsx?$/, babelTransform))
    .pipe(gulp.dest('bin'))
    .pipe(gulpif(unlinkEvent, vinylPaths(del)))
})