gulp with babel auto-watcher

gulpfile.js

const gulp = require('gulp');
const babel = require('gulp-babel');

// default task set to auto-watch.
gulp.task('default', function () {
  gulp.watch('js/*', ['babel']);
});

// babel task
gulp.task('babel', function () {

  return gulp.src('js/*')
      .pipe(babel({
          presets: ['es2015']
      }))
      .pipe(gulp.dest('dist'))

});

package.json

{
  "name": "test",
  "version": "1.0.0",
  "description": "",
  "main": "index.js",
  "directories": {
    "test": "tests"
  },
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1"
  },
  "author": "",
  "license": "ISC",
  "devDependencies": {
    "babel-preset-es2015": "^6.24.1",
    "gulp": "^3.9.1",
    "gulp-babel": "^6.1.2"
  }
}