updated gulpfiles to gulp4

web/modules/custom/gulpfile.js

@@ -33,38 +33,41 @@ function handleError(err) {
   console.log(err.toString());
 }
 
-gulp.task('scripts', function () {
-  var tasks = modules.map(function(module) {
-    return gulp.src('./'+module+'/assets/scripts/*.js')
-      .pipe(gulpif(prod, stripDebug()))
-      .pipe(gulpif(prod, jsmin()))
-      .pipe(rename({suffix: '.min'}))
-      .pipe(gulp.dest('./'+module+'/assets/dist/scripts/'));
+gulp.task('scripts', function (done) {
+  return new Promise(function(resolve, reject) {
+    modules.map(function(module) {
+      gulp.src('./'+module+'/assets/scripts/*.js')
+        .pipe(gulpif(prod, stripDebug()))
+        .pipe(gulpif(prod, jsmin()))
+        .pipe(rename({suffix: '.min'}))
+        .pipe(gulp.dest('./'+module+'/assets/dist/scripts/'));
+    });
+    resolve();
   });
-  return es.merge.apply(null, tasks);
 });
 
-gulp.task('styles', function () {
-  var tasks = modules.map(function(module) {
-    return gulp.src('./'+module+'/assets/styles/*.scss')
-      .pipe(sass().on('error', sass.logError))
-      .pipe(autoprefixer({
-          browsers: ['last 2 versions'],
-          cascade: false
-      })).on('error', handleError)
-      .pipe(gulpif(prod, cssmin()))
-      // .pipe(cssmin())
-      .pipe(rename({suffix: '.min'}))
-      .pipe(gulp.dest('./'+module+'/assets/dist/styles/'));
+gulp.task('styles', function (done) {
+  return new Promise(function(resolve, reject) {
+    modules.map(function(module) {
+      gulp.src('./'+module+'/assets/styles/*.scss')
+        .pipe(sass().on('error', sass.logError))
+        .pipe(autoprefixer({
+            cascade: false
+        })).on('error', handleError)
+        .pipe(gulpif(prod, cssmin()))
+        // .pipe(cssmin())
+        .pipe(rename({suffix: '.min'}))
+        .pipe(gulp.dest('./'+module+'/assets/dist/styles/'));
+    });
+    resolve();
   });
-  return es.merge.apply(null, tasks);
 });
 
 // default gulp task
-gulp.task('default', ['scripts', 'styles'], function() { //'bower',
+gulp.task('default', gulp.series('scripts', 'styles', done => {
   for (var i = 0; i < modules.length; i++) {
-    // gulp.watch('./assets/styles/*/*.scss', ['styles']);
-    gulp.watch('./'+modules[i]+'/assets/styles/*.scss', ['styles']);
-    gulp.watch('./'+modules[i]+'/assets/scripts/*.js', ['scripts']);
+    gulp.watch('./'+modules[i]+'/assets/styles/*.scss', gulp.series('styles'));
+    gulp.watch('./'+modules[i]+'/assets/scripts/*.js', gulp.series('scripts'));
   }
-});
+  done()
+}));