Add some comments

README.md

@@ -506,7 +506,6 @@ custom:
 This can be useful, in case you want to upload the source maps to your Error
 reporting system, or just have it available for some post processing.
 
-
 #### Nodejs custom runtime
 
 If you are using a nodejs custom runtime you can add the property `allowCustomRuntime: true`.
@@ -520,6 +519,7 @@ exampleFunction:
 
 ⚠️ **Note: this will only work if your custom runtime and function are written in JavaScript.
 Make sure you know what you are doing when this option is set to `true`**
+
 #### Examples
 
 You can find an example setups in the [`examples`][link-examples] folder.

lib/packageModules.js

@@ -26,13 +26,17 @@ function setArtifactPath(funcName, func, artifactPath) {
   }
 }
 
+/**
+ * Copy pasted from Serverless
+ *
+ * @see https://github.com/serverless/serverless/blob/63d54e1537e10ae63c171892edd886f6b81e83f6/lib/plugins/package/lib/zipService.js#L65
+ */
 function serverlessZip(args) {
-  const artifactFilePath = args.artifactFilePath;
-  const directory = args.directory;
-  const files = args.files;
+  const { artifactFilePath, directory, files } = args;
 
   const zip = archiver.create('zip');
   const output = fs.createWriteStream(artifactFilePath);
+
   return new BbPromise((resolve, reject) => {
     output.on('close', () => resolve(artifactFilePath));
     output.on('error', err => reject(err));
@@ -56,7 +60,9 @@ function serverlessZip(args) {
               zip.append(file.data, {
                 name,
                 mode,
-                date: new Date(0) // necessary to get the same hash when zipping the same content
+                // necessary to get the same hash when zipping the same content
+                // as well as `contents.sort` few lines above
+                date: new Date(0)
               });
             }
           );
@@ -68,8 +74,14 @@ function serverlessZip(args) {
   });
 }
 
+/**
+ * Copy pasted from Serverless
+ *
+ * @see https://github.com/serverless/serverless/blob/63d54e1537e10ae63c171892edd886f6b81e83f6/lib/plugins/package/lib/zipService.js#L112
+ */
 function getFileContentAndStat(directory, filePath) {
   const fullPath = `${directory}/${filePath}`;
+
   return BbPromise.all([
     // Get file contents and stat in parallel
     getFileContent(fullPath),
@@ -89,11 +101,16 @@ function getFileContentAndStat(directory, filePath) {
   );
 }
 
+/**
+ * Copy pasted from Serverless
+ *
+ * @see https://github.com/serverless/serverless/blob/63d54e1537e10ae63c171892edd886f6b81e83f6/lib/plugins/package/lib/zipService.js#L135
+ */
 function getFileContent(fullPath) {
   return fs.readFileAsync(fullPath);
 }
 
-function zip(directory, name) {
+function zip(directory, zipFileName) {
   // Check that files exist to be zipped
   let files = glob.sync('**', {
     cwd: directory,
@@ -123,12 +140,12 @@ function zip(directory, name) {
 
   // Create artifact in temp path and move it to the package path (if any) later
   // This allows us to persist the webpackOutputPath and re-use the compiled output
-  const artifactFilePath = path.join(this.webpackOutputPath, name);
+  const artifactFilePath = path.join(this.webpackOutputPath, zipFileName);
   this.serverless.utils.writeFileDir(artifactFilePath);
 
   return serverlessZip({
-    artifactFilePath,
     directory,
+    artifactFilePath,
     files
   });
 }