Gulp Babel

gulpfile.js

const babel = require("gulp-babel")
const cache = require("gulp-cached")
const gulp = require("gulp")
const plumber = require("gulp-plumber")

gulp.task("compile", () =>
	gulp.src("src/**/*.js")
		.pipe(plumber())
		.pipe(cache("babel"))
		.pipe(babel())
		.pipe(gulp.dest("lib"))
)

gulp.task("watch", () =>
	gulp.watch("src/**/*.js", ["compile"])
)

gulp.task("default", ["watch", "compile"])