Migrate to Gulp 4 and Babel 7 (monorepo)

gulpfile.js

@@ -3,27 +3,37 @@
 const gulp = require('gulp');
 // Require gulp-babel
 const babel = require('gulp-babel');
+const watchPath = 'src/app.js'
 
-// Create an es6 task
-gulp.task('es6', () => {
+// Create an babelPresetEnv task
+gulp.task('babelPresetEnv', () => {
 	// Return gulp.src with the src set to our src folder
 	// we return here do that we indicate to gulp that this task is async
-	return gulp.src('src/app.js')
+	return gulp.src(watchPath)
 		// We pipe the source into babel
 		.pipe(babel({
-			// We need to tell babel to use the babel-preset-es2015
-			presets: ['es2015']
+			// We need to tell babel to use the @babel/preset-env
+			presets: [
+				[
+					'@babel/preset-env', {
+						'targets': {
+							'browsers': '> 0.1%, not dead'
+						},
+						'debug': true
+					}
+				]
+			]
 		}))
 		// We then pipe that into gulp.dest to set a final destination
 		// In this case a build folder
 		.pipe(gulp.dest('build'));
 });
 // Create a default gulp task, this lets us type gulp into the terminal
-// The ['es6'] tells gulp what task or tasks to run right away. 
-gulp.task('default', ['es6'],() => {
+// The ['babelPresetEnv'] tells gulp what task or tasks to run right away.
+gulp.task('default', gulp.series('babelPresetEnv',() => {
 	// Tell gulp to watch for file changes on src/app.js
-	// run the es6 task when it changes!
-	gulp.watch('src/app.js',['es6'])
-});
+	// run the babelPresetEnv task when it changes!
+	gulp.watch(watchPath, gulp.series('babelPresetEnv'));
+}));