From 7703ba2387134e297c324cf2de3baf60e62e0aa4 Mon Sep 17 00:00:00 2001
From: Brandon Roberts <robertsbt@gmail.com>
Date: Thu, 31 Mar 2016 22:38:17 -0500
Subject: [PATCH] feat(directives): Added linkTo directive

---
 lib/index.ts    |  5 +++-
 lib/link-to.ts  | 73 +++++++++++++++++++++++++++++++++++++++++++++++++
 lib/location.ts |  8 ++++--
 3 files changed, 83 insertions(+), 3 deletions(-)
 create mode 100644 lib/link-to.ts

diff --git a/lib/index.ts b/lib/index.ts
index d1015a5..a4f4dbf 100644
--- a/lib/index.ts
+++ b/lib/index.ts
@@ -12,6 +12,7 @@ import { GUARD_PROVIDERS } from './guard';
 import { MATCH_ROUTE_PROVIDERS } from './match-route';
 import { COMPONENT_RENDERER_PROVIDERS } from './component-renderer';
 import { QUERY_PARAMS_PROVIDERS } from './query-params';
+import { LINK_TO_PROVIDERS } from './link-to';
 
 export function provideRouter(routes: Routes) {
   return [
@@ -25,7 +26,8 @@ export function provideRouter(routes: Routes) {
     GUARD_PROVIDERS,
     MATCH_ROUTE_PROVIDERS,
     COMPONENT_RENDERER_PROVIDERS,
-    QUERY_PARAMS_PROVIDERS
+    QUERY_PARAMS_PROVIDERS,
+    LINK_TO_PROVIDERS
   ];
 }
 
@@ -39,3 +41,4 @@ export { usePreRenderMiddleware, usePostRenderMiddleware, RenderInstruction } fr
 export { Routes, Route, IndexRoute } from './route';
 export { useTraversalMiddleware } from './match-route';
 export { QueryParams } from './query-params';
+export { LinkTo } from './link-to';
diff --git a/lib/link-to.ts b/lib/link-to.ts
new file mode 100644
index 0000000..4ac54d1
--- /dev/null
+++ b/lib/link-to.ts
@@ -0,0 +1,73 @@
+import {
+  Directive,
+  HostBinding,
+  HostListener,
+  Input,
+  PLATFORM_DIRECTIVES,
+  provide,
+  Provider
+} from  'angular2/core';
+import { Location } from './location';
+
+/**
+ * The LinkTo directive links to routes in your app
+ *
+ * Links are pushed to the `Location` service to trigger a route change.
+ * Query params can be represented as an object or a string of names/values
+ *
+ * <a linkTo="/home/page" [queryParams]="{ id: 123 }">Home Page</a>
+ * <a [linkTo]="'/pages' + page.id">Page 1</a>
+ */
+@Directive({ selector: '[linkTo]' })
+export class LinkTo {
+  @Input() target: string;
+  @HostBinding('attr.href') linkHref;
+
+  @Input() set linkTo(href: string){
+    this._href = href;
+    this._updateHref();
+  }
+
+  @Input() set queryParams(params: string | Object) {
+    this._query = params;
+    this._updateHref();
+  }
+
+  private _href: string;
+  private _query: string | Object;
+
+  constructor(private _location: Location) {}
+
+  /**
+   * Handles click events on the associated link
+   * Prevents default action for non-combination click events without a target
+   */
+  @HostListener('click', ['$event'])
+  onClick(event) {
+    if (!this._comboClick(event) && !this.target) {
+      this._location.go(this._href, this._query);
+
+      event.preventDefault();
+    }
+  }
+
+  private _updateHref() {
+    this.linkHref = this._location.prepareExternalUrl(this._href, this._query);
+  }
+
+  /**
+   * Determines whether the click event happened with a combination of other keys
+   */
+  private _comboClick(event) {
+    let buttonEvent = event.which || event.button;
+
+    return (buttonEvent > 1 || event.ctrlKey || event.metaKey || event.shiftKey);
+  }
+}
+
+export const LINK_TO_PROVIDERS = [
+  provide(PLATFORM_DIRECTIVES, {
+    multi: true,
+    useValue: [ LinkTo ]
+  })
+];
diff --git a/lib/location.ts b/lib/location.ts
index f8fff4f..3adc5be 100644
--- a/lib/location.ts
+++ b/lib/location.ts
@@ -95,11 +95,11 @@ export class Location extends ReplaySubject<LocationChange>{
    * before normalizing. This method will also add a hash if `HashLocationStrategy` is
    * used, or the `APP_BASE_HREF` if the `PathLocationStrategy` is in use.
    */
-  prepareExternalUrl(url: string): string {
+  prepareExternalUrl(url: string, query: any = ''): string {
     if (url.length > 0 && !url.startsWith('/')) {
       url = '/' + url;
     }
-    return this.platformStrategy.prepareExternalUrl(url);
+    return this.platformStrategy.prepareExternalUrl(url + normalizeQueryParams(normalizeQuery(query)));
   }
 
   /**
@@ -161,6 +161,10 @@ function normalizeQuery(query: any) {
   return typeof query === 'string' ? query : stringifyQueryParams(query);
 }
 
+function normalizeQueryParams(params: string): string {
+  return (params.length > 0 && params.substring(0, 1) != '?') ? ('?' + params) : params;
+}
+
 export const LOCATION_PROVIDERS = [
   provide(Location, { useClass: Location }),
   provide(PlatformLocation, { useClass: BrowserPlatformLocation })