Better define an Require JS alias and preference

- Take notes from Magento devdocs to better explain Require JS alias, previous was more of a preference.
- Take notes from Magento devdocs to better explain Require JS preference, previous was more of an alias.

Author: portchris

3. Customizing the Magento UI/4. Utilize JavaScript in Magento.md

@@ -224,24 +224,27 @@ it’s easier and more effective to use a UI component.
 We are interested in:
 - map as alias - same as defining virtual type preference in DI
 ```js
-var config = {
-    map: {
-        '*': {
-            'Magento_Swatches/js/swatch-renderer' : 'Custom_Module/js/swatch-renderer'
-        }
+map: {
+    '*': {
+        alias: 'Vendor_Module/js/complex/path/amd-module'
     }
-};
+}
 ```
+Now we can use our 'Vendor_Module/js/complex/path/module' using `alias` in any RequireJS module or config file without needing to type the entire path. For example, in Magento, `catalogAddToCart` is mapped to 'Magento_Catalog/js/catalog-add-to-cart' and can be used anywhere as a RequireJS module name.
+
 - map as preference - same as preference in DI, replace one class with another
 ```js
 var config = {
-    map: {
-        '*': {
-            uiElement:      'Magento_Ui/js/lib/core/element/element',
-        }
+  "map": {
+    "*": {
+      "<default_component>": "<custom_component>"
     }
+  }
 };
 ```
+* <default_component>: the name of the default component you replace
+* <custom_component>: the name of the custom component
+
 - mixins - same as around plugins in DI. This is Magento customization over requireJS
 ```js
 var config = {