feat(core): add support for @HostBinding and @HostListener

Example:

@Directive({selector: 'my-directive'})
class MyDirective {
  @HostBinding("attr.my-attr") myAttr: string;
  @HostListener("click", ["$event.target"])
  onClick(target) {
    this.target = target;
  }
}

Closes #3996

modules/angular2/src/core/compiler/directive_resolver.ts

@@ -1,11 +1,13 @@
 import {resolveForwardRef, Injectable} from 'angular2/di';
 import {Type, isPresent, BaseException, stringify} from 'angular2/src/core/facade/lang';
-import {ListWrapper, StringMapWrapper} from 'angular2/src/core/facade/collection';
+import {ListWrapper, StringMap, StringMapWrapper} from 'angular2/src/core/facade/collection';
 import {
   DirectiveMetadata,
   ComponentMetadata,
   PropertyMetadata,
-  EventMetadata
+  EventMetadata,
+  HostBindingMetadata,
+  HostListenerMetadata
 } from 'angular2/metadata';
 import {reflector} from 'angular2/src/core/reflection/reflection';
 
@@ -40,6 +42,7 @@ export class DirectiveResolver {
                                          StringMap<string, any[]>): DirectiveMetadata {
     var properties = [];
     var events = [];
+    var host = {};
 
     StringMapWrapper.forEach(propertyMetadata, (metadata: any[], propName: string) => {
       metadata.forEach(a => {
@@ -58,23 +61,37 @@ export class DirectiveResolver {
             events.push(propName);
           }
         }
+
+        if (a instanceof HostBindingMetadata) {
+          if (isPresent(a.hostPropertyName)) {
+            host[`[${a.hostPropertyName}]`] = propName;
+          } else {
+            host[`[${propName}]`] = propName;
+          }
+        }
+
+        if (a instanceof HostListenerMetadata) {
+          var args = isPresent(a.args) ? a.args.join(', ') : '';
+          host[`(${a.eventName})`] = `${propName}(${args})`;
+        }
       });
     });
-
-    return this._merge(dm, properties, events);
+    return this._merge(dm, properties, events, host);
   }
 
-  private _merge(dm: DirectiveMetadata, properties: string[], events: string[]): DirectiveMetadata {
+  private _merge(dm: DirectiveMetadata, properties: string[], events: string[],
+                 host: StringMap<string, string>): DirectiveMetadata {
     var mergedProperties =
         isPresent(dm.properties) ? ListWrapper.concat(dm.properties, properties) : properties;
     var mergedEvents = isPresent(dm.events) ? ListWrapper.concat(dm.events, events) : events;
+    var mergedHost = isPresent(dm.host) ? StringMapWrapper.merge(dm.host, host) : host;
 
     if (dm instanceof ComponentMetadata) {
       return new ComponentMetadata({
         selector: dm.selector,
         properties: mergedProperties,
         events: mergedEvents,
-        host: dm.host,
+        host: mergedHost,
         lifecycle: dm.lifecycle,
         bindings: dm.bindings,
         exportAs: dm.exportAs,
@@ -88,7 +105,7 @@ export class DirectiveResolver {
         selector: dm.selector,
         properties: mergedProperties,
         events: mergedEvents,
-        host: dm.host,
+        host: mergedHost,
         lifecycle: dm.lifecycle,
         bindings: dm.bindings,
         exportAs: dm.exportAs,

modules/angular2/src/core/metadata.dart

@@ -112,3 +112,19 @@ class Event extends EventMetadata {
   const Event([String bindingPropertyName])
     : super(bindingPropertyName);
 }
+
+/**
+ * See: [HostBindingMetadata] for docs.
+ */
+class HostBinding extends HostBindingMetadata {
+  const HostBinding([String hostPropertyName])
+    : super(hostPropertyName);
+}
+
+/**
+ * See: [HostListenerMetadata] for docs.
+ */
+class HostListener extends HostListenerMetadata {
+  const HostListener(String eventName, [List<String> args])
+    : super(eventName, args);
+}

modules/angular2/src/core/metadata.ts

@@ -15,7 +15,9 @@ export {
   PipeMetadata,
   LifecycleEvent,
   PropertyMetadata,
-  EventMetadata
+  EventMetadata,
+  HostBindingMetadata,
+  HostListenerMetadata
 } from './metadata/directives';
 
 export {ViewMetadata, ViewEncapsulation} from './metadata/view';
@@ -33,7 +35,9 @@ import {
   PipeMetadata,
   LifecycleEvent,
   PropertyMetadata,
-  EventMetadata
+  EventMetadata,
+  HostBindingMetadata,
+  HostListenerMetadata
 } from './metadata/directives';
 
 import {ViewMetadata, ViewEncapsulation} from './metadata/view';
@@ -447,6 +451,45 @@ export interface EventFactory {
   new (bindingPropertyName?: string): any;
 }
 
+/**
+ * {@link HostBindingMetadata} factory for creating decorators.
+ *
+ * ## Example as TypeScript Decorator
+ *
+ * ```
+ * @Directive({
+ *   selector: 'sample-dir'
+ * })
+ * class SampleDir {
+ *   @HostBinding() prop1; // Same as @HostBinding('prop1') prop1;
+ *   @HostBinding("el-prop") prop1;
+ * }
+ * ```
+ */
+export interface HostBindingFactory {
+  (hostPropertyName?: string): any;
+  new (hostPropertyName?: string): any;
+}
+
+/**
+ * {@link HostListenerMetadata} factory for creating decorators.
+ *
+ * ## Example as TypeScript Decorator
+ *
+ * ```
+ * @Directive({
+ *   selector: 'sample-dir'
+ * })
+ * class SampleDir {
+ *   @HostListener("change", ['$event.target.value']) onChange(value){}
+ * }
+ * ```
+ */
+export interface HostListenerFactory {
+  (eventName: string, args?: string[]): any;
+  new (eventName: string, args?: string[]): any;
+}
+
 /**
  * {@link ComponentMetadata} factory function.
  */
@@ -492,4 +535,14 @@ export var Property: PropertyFactory = makePropDecorator(PropertyMetadata);
 /**
  * {@link EventMetadata} factory function.
  */
-export var Event: EventFactory = makePropDecorator(EventMetadata);
+export var Event: EventFactory = makePropDecorator(EventMetadata);
+
+/**
+ * {@link HostBindingMetadata} factory function.
+ */
+export var HostBinding: HostBindingFactory = makePropDecorator(HostBindingMetadata);
+
+/**
+ * {@link HostListenerMetadata} factory function.
+ */
+export var HostListener: HostListenerFactory = makePropDecorator(HostListenerMetadata);

modules/angular2/src/core/metadata/directives.ts

@@ -1109,4 +1109,68 @@ export class PropertyMetadata {
 @CONST()
 export class EventMetadata {
   constructor(public bindingPropertyName?: string) {}
+}
+
+/**
+ * Declare a host property binding.
+ *
+ * ## Example
+ *
+ * ```
+ * @Directive({
+ *   selector: 'sample-dir'
+ * })
+ * class SampleDir {
+ *   @HostBinding() prop1; // Same as @HostBinding('prop1') prop1;
+ *   @HostBinding("el-prop") prop2;
+ * }
+ * ```
+ *
+ * This is equivalent to
+ *
+ * ```
+ * @Directive({
+ *   selector: 'sample-dir',
+ *   host: {'[prop1]': 'prop1', '[el-prop]': 'prop2'}
+ * })
+ * class SampleDir {
+ *   prop1;
+ *   prop2;
+ * }
+ * ```
+ */
+@CONST()
+export class HostBindingMetadata {
+  constructor(public hostPropertyName?: string) {}
+}
+
+/**
+ * Declare a host listener.
+ *
+ * ## Example
+ *
+ * ```
+ * @Directive({
+ *   selector: 'sample-dir'
+ * })
+ * class SampleDir {
+ *   @HostListener("change", ['$event.target.value']) onChange(value){}
+ * }
+ * ```
+ *
+ * This is equivalent to
+ *
+ * ```
+ * @Directive({
+ *   selector: 'sample-dir',
+ *   host: {'(change)': 'onChange($event.target.value)'}
+ * })
+ * class SampleDir {
+ *   onChange(value){}
+ * }
+ * ```
+ */
+@CONST()
+export class HostListenerMetadata {
+  constructor(public eventName: string, public args?: string[]) {}
 }