Update doc about excludeRegex

Also:
- dump a message to log how files were excluded (might be good for debugging)
- update unit test to actually match the type of `excludeRegex` from the configuration (which is not a regex but a string)

README.md

@@ -463,7 +463,7 @@ regex you want to exclude).
 # serverless.yml
 custom:
   webpack:
-    excludeRegex: /\.ts|test|\.map/
+    excludeRegex: \.ts|test|\.map
 ```
 
 #### Keep output directory after packaging

lib/packageModules.js

@@ -35,15 +35,18 @@ function zip(directory, name) {
     nodir: true
   });
 
-  const files = this.configuration.excludeRegex
-    ? _.filter(globFiles, f => f.match(this.configuration.excludeRegex) === null)
-    : globFiles;
-  if (files.length < globFiles.length && this.options.verbose) {
-    this.serverless.cli.log(`Excluded ${globFiles.length - files.length} file(s) based on excludeRegex`);
+  let files = globFiles;
+  if (this.configuration.excludeRegex) {
+    files = _.filter(globFiles, f => f.match(this.configuration.excludeRegex) === null);
+
+    if (this.options.verbose) {
+      this.serverless.cli.log(`Excluded ${globFiles.length - files.length} file(s) based on excludeRegex`);
+    }
   }
 
   if (_.isEmpty(files)) {
     const error = new this.serverless.classes.Error('Packaging: No files found');
+
     return BbPromise.reject(error);
   }
 
@@ -52,14 +55,12 @@ function zip(directory, name) {
   const artifactFilePath = path.join(this.webpackOutputPath, name);
   this.serverless.utils.writeFileDir(artifactFilePath);
 
-  const cwd = directory;
-  const source = files;
-  const destination = path.relative(cwd, artifactFilePath);
   const zipArgs = {
-    source,
-    cwd,
-    destination
+    source: files,
+    cwd: directory,
+    destination: path.relative(directory, artifactFilePath)
   };
+
   return new BbPromise((resolve, reject) => {
     bestzip(zipArgs)
       .then(() => {

tests/packageModules.test.js

@@ -312,7 +312,7 @@ describe('packageModules', () => {
       it('should reject if no files are found because all files are excluded using regex', () => {
         module.configuration = new Configuration({
           webpack: {
-            excludeRegex: /.*/
+            excludeRegex: '.*'
           }
         });