improvement: Added Docs/try,catch

Added docs explaining what the argument does.
Added try/catch around fs.writeFile()

commands/publish/README.md

@@ -65,6 +65,7 @@ This is useful when a previous `lerna publish` failed to publish all packages to
 - [`--tag-version-prefix`](#--tag-version-prefix)
 - [`--temp-tag`](#--temp-tag)
 - [`--yes`](#--yes)
+- [`--summary-file <dir/filename>`](#--summary-file)
 
 ### `--canary`
 
@@ -291,6 +292,27 @@ lerna publish --canary --yes
 When run with this flag, `lerna publish` will skip all confirmation prompts.
 Useful in [Continuous integration (CI)](https://en.wikipedia.org/wiki/Continuous_integration) to automatically answer the publish confirmation prompt.
 
+### `--summary-file`
+
+```sh
+lerna publish --canary --yes --summary-file ./output.json
+```
+
+When run with this flag, once a successfully publish it will create a json summary report(see below for an example).
+
+```json
+[
+  {
+    "packageName": "package1",
+    "version": "v1.0.1-alpha"
+  },
+  {
+    "packageName": "package2",
+    "version": "v2.0.1-alpha"
+  }
+]
+```
+
 ## Deprecated Options
 
 ### `--skip-npm`

commands/publish/index.js

@@ -252,8 +252,12 @@ class PublishCommand extends Command {
           };
         });
         output(jsonObject);
-        // TODO: Add error handling so it won't crash if it fails.
-        fs.writeFileSync(filePath, JSON.stringify(jsonObject));
+        try {
+          fs.writeFileSync(filePath, JSON.stringify(jsonObject));
+          output("Locate Summary Report Here: ", filePath);
+        } catch (error) {
+          output("Failed to create the summary report", error);
+        }
       } else {
         const message = this.packagesToPublish.map(pkg => ` - ${pkg.name}@${pkg.version}`);
         output(message.join(os.EOL));