gulpfile.babel.js

import gulp from 'gulp';
import babel from 'gulp-babel';
import eslint from 'gulp-eslint';
import sourcemaps from 'gulp-sourcemaps';
import notify from 'gulp-notify';
import plumber from 'gulp-plumber';

var filePath = {
	js: 'src/**/*.js'
};

gulp.task('lint', () => {
	// ESLint ignores files with "node_modules" paths.
	// So, it's best to have gulp ignore the directory as well.
	// Also, Be sure to return the stream from the task;
	// Otherwise, the task may end before the stream has finished.
	return gulp.src( filePath.js )
		// eslint() attaches the lint output to the "eslint" property
		// of the file object so it can be used by other modules.
		.pipe(eslint())
		// eslint.format() outputs the lint results to the console.
		// Alternatively use eslint.formatEach() (see Docs).
		.pipe(eslint.format())
		// To have the process exit with an error code (1) on
		// lint error, return the stream and pipe to failAfterError last.
		.pipe(eslint.failAfterError());
});

gulp.task('js', () => {
	return gulp.src( filePath.js )
		.pipe(plumber())
		.pipe(sourcemaps.init())
			.pipe(babel({
				presets: [ 'es2015', 'stage-0' ]
			}))
		.pipe(sourcemaps.write())
		.pipe(gulp.dest('dist'))
		.pipe(notify({ message: 'Project successfully built!', onLast: true } ));
});

gulp.task('watch-js', () => {
	gulp.watch(filePath.js, [ 'js' ]);
});

gulp.task('default', [ 'js', 'watch-js' ]);