Update documentation for Events in elemental2

Author: adrienbaron

docs-source/book/composition/render-function.md

@@ -363,15 +363,15 @@ Here's an example with all of these modifiers used together:
 
 ```java
 vNodeData.on("keyup", (param) -> {
-    NativeEvent event = (NativeEvent) param;
+    KeyboardEvent event = (KeyboardEvent) param;
 
     // Abort if the element emitting the event is not
     // the element the event is bound to
-    if (event.getEventTarget() != event.getCurrentEventTarget()) return;
+    if (event.target != event.currentTarget) return;
     // Abort if the key that went up is not the enter
-    // key (13) and the shift key was not held down
+    // and the shift key was not held down
     // at the same time
-    if (!event.getShiftKey() || event.getKeyCode() !== 13) return;
+    if (!event.shiftKey || !"Enter".equals(event.code)) return;
     // Stop event propagation
     event.stopPropagation();
     // Prevent the default keyup handler for this element

docs-source/book/essential/components.md

@@ -590,7 +590,7 @@ is just syntactic sugar for:
 ```html
 <input
   v-bind:value="something"
-  v-on:input="setSomethingValue((NativeEvent) $event)">
+  v-on:input="setSomethingValue((Event) $event)">
 ```
 
 When used with a component, this simplifies to:

docs-source/book/essential/events.md

@@ -101,31 +101,35 @@ Sometimes we also need to access the original DOM event in an inline statement h
 You can pass it into a method using the special `$event` variable:
 
 ```html
-<button v-on:click='warn("Form cannot be submitted yet.", (NativeEvent) $event)'>
+<button v-on:click='warn("Form cannot be submitted yet.", (Event) $event)'>
     Submit
 </button>
 ```
 
 ```java
 // ...
-public void warn(String message, NativeEvent event) {
+public void warn(String message, Event event) {
     if (event != null) {
         event.preventDefault();
-        message += " -> Event Type: " + event.getType();
+        message += " -> Event Type: " + event.type;
     }
 
     Window.alert(message);
 }
 ```
 
-You will notice that we cast the `$event` variable to `NativeEvent` in our template.
+You will notice that we cast the `$event` variable to `Event` in our template.
 This is to indicate the type of the `$event` variable to Vue GWT.
 
-This means that if your `warn` method was actually declared like this: `void warn(NativeEvent event, String message)` it would break at compile time with an explicit error.
+This means that if your `warn` method was actually declared like this: `void warn(Event event, String message)` it would break at compile time with an explicit error.
 
-You don't have to import the `NativeEvent` class to use it in your template.
+You don't have to import the `Event` class to use it in your template.
 It's already imported by default for convenience.
 
+`Event` comes from [Elemental2](https://github.com/google/elemental2).
+It is the base for all DOM events.
+You cast it to more specific events like `MouseEvent` or `KeyboardEvent` in your Component class. 
+
 You'll see further that `$event` can also be used when communicating between Components.
 In those case you might cast it to another type, like `Todo` for example.
 

docs-source/book/essential/forms.md

@@ -75,8 +75,8 @@ public class TodoTextComponent extends VueComponent {
     @JsProperty Todo todo = new Todo("Hello World!");
 
     @JsMethod
-    public void updateMessage(NativeEvent event) {
-        this.todo.setText(JsTools.get(event.getEventTarget(), "value"));
+    public void updateMessage(Event event) {
+        this.todo.setText(((HTMLInputElement) event.target).value);
     }
 }
 ```