fix(all): fix gulp and add Webpack ESLint

Author: jpatovh

index.js

@@ -37,6 +37,28 @@ module.exports = (gulp, userConfig, tasks) => {
 
   /* eslint-enable global-require */
 
+  // This is a fix fo Gulp, because series and paparallel needs at least one task
+  gulp.task('nothing-to-do', function (done) { return done(); });
+
+  if (!tasks.clean.length) {
+    tasks.clean.push('nothing-to-do');
+  }
+  if (!tasks.compile.length) {
+    tasks.compile.push('nothing-to-do');
+  }
+  if (!tasks.validate.length) {
+    tasks.validate.push('nothing-to-do');
+  }
+  if (!tasks.test.length) {
+    tasks.test.push('nothing-to-do');
+  }
+  if (!tasks.watch.length) {
+    tasks.watch.push('nothing-to-do');
+  }
+  if (!tasks.default.length) {
+    tasks.default.push('nothing-to-do');
+  }
+
   // Instead of `gulp.parallel`, which is what is set in Pattern Lab Starter's `gulpfile.js`, this
   // uses `gulp.series`. Needed to help with the Gulp task dependencies lost going from v3 to v4.
   // We basically need icons compiled before CSS & CSS/JS compiled before inject:pl before pl

lib/webpack.js

@@ -1,5 +1,7 @@
 'use strict';
 
+const eslint = require('gulp-eslint');
+const cached = require('gulp-cached');
 const webpack = require('webpack');
 const browserSync = require('browser-sync');
 const core = require('./core');
@@ -17,6 +19,22 @@ Note: you can copy the template from templates/webpack.config.js.
     process.exit(1);
   }
 
+  function validateJs() {
+    return gulp.src(config.webpack.eslint.src)
+      .pipe(cached('validate:webpack'))
+      .pipe(eslint())
+      .pipe(eslint.format());
+  }
+
+  validateJs.description = 'Lint Webpack.';
+
+  if (config.webpack.eslint.enabled) {
+    gulp.task('validate:webpack', () => validateJs().pipe(eslint.failAfterError()));
+    tasks.validate.push('validate:webpack');
+    gulp.task('watch:validate:webpack', () => gulp.watch(config.webpack.eslint.src, validateJs));
+    tasks.watch.push('watch:validate:webpack');
+  }
+
   function compileWebpack() {
     return gulp.src(config.webpack.config)
       .pipe(function runCompileWebpack() {

templates/gulpfile.js

@@ -24,7 +24,7 @@ gulp.task('compile', gulp.series(
   'clean',
   gulp.series(tasks.compile)
 ));
-gulp.task('build', ['compile']);   // alias
+gulp.task('build', gulp.series(['compile']));   // alias
 gulp.task('validate', gulp.parallel(tasks.validate));
 gulp.task('test', gulp.parallel(tasks.test));
 gulp.task('watch', gulp.parallel(tasks.watch));