fixes from code review

atom/browser/api/atom_api_system_preferences_mac.mm

@@ -146,13 +146,13 @@ v8::Local<v8::Value> SystemPreferences::GetUserDefault(
 
 void SystemPreferences::RegisterDefaults(mate::Arguments* args) {
   base::DictionaryValue value;
-  if (!args->GetNext(&value)) {
-    args->ThrowError("Unable to parse userDefaults dict");
-    return;
-  }
-
-  if (NSDictionary* dict = DictionaryValueToNSDictionary(value)) {
+  args->GetNext(&value);
+  
+  @try {
+    NSDictionary* dict = DictionaryValueToNSDictionary(value);
     [[NSUserDefaults standardUserDefaults] registerDefaults:dict];
+  } @catch (NSException* exception) {
+    args->ThrowError("Invalid userDefault data provided");
   }
 }
 

docs/api/system-preferences.md

@@ -109,8 +109,8 @@ Same as `unsubscribeNotification`, but removes the subscriber from `NSNotificati
 ### `systemPreferences.registerDefaults(defaults)` _macOS_
 
 * `defaults` Object - a dictionary of (`key: value`) user defaults
-  * `key` String - must be of type `string`
-  * `value` Object - object of type `string`, `boolean`, `integer`, `float`, `double`,
+  * `key` String
+  * `value` (String | Boolean | Number) - object of type `string`, `boolean`, `integer`, `float`, `double`,
     `url`, `array`, or `dictionary`.
 
 Allows for registering of your application's preference defaults in `NSUserDefaults`.

spec/api-system-preferences-spec.js

@@ -42,25 +42,25 @@ describe('systemPreferences module', () => {
 
     it('registers defaults', () => {
       const userDefaults = {
-        'one': 'onee',
-        'two': 'twoo',
-        'three': 'threee',
-        'four': 'fourr',
-        'five': 'fivee'
+        'one': 'ONE',
+        'two': 'TWO',
+        'three': 'THREE'
       }
 
       systemPreferences.registerDefaults(userDefaults)
 
-      const val = systemPreferences.getUserDefault('two', 'string')
-      assert.equal(val, 'twoo')
+      for (const [key, expectedValue] of Object.entries(userDefaults)) {
+        const actualValue = systemPreferences.getUserDefault(key, 'string')
+        assert.equal(actualValue, expectedValue)
+      }
     })
 
     it('throws when bad defaults are passed', () => {
-      const userDefaults = 1
+      const badDefaults1 = { 'one': null }
 
       assert.throws(() => {
-        systemPreferences.setUserDefault(userDefaults)
-      }, `Unable to parse userDefaults dict`)
+        systemPreferences.registerDefaults(badDefaults1)
+      }, 'Invalid userDefault data provided')
     })
   })