feat(router): add support for route links with no leading slash

Closes #4623

modules/angular2/src/router/route_registry.ts

@@ -254,6 +254,14 @@ export class RouteRegistry {
     return instruction;
   }
 
+  public hasRoute(name: string, parentComponent: any): boolean {
+    var componentRecognizer: RouteRecognizer = this._rules.get(parentComponent);
+    if (isBlank(componentRecognizer)) {
+      return false;
+    }
+    return componentRecognizer.hasRoute(name);
+  }
+
   // if the child includes a redirect like : "/" -> "/something",
   // we want to honor that redirection when creating the link
   private _generateRedirects(componentCursor: Type): Instruction {

modules/angular2/src/router/router.ts

@@ -432,8 +432,21 @@ export class Router {
         }
       }
     } else if (first != '.') {
-      throw new BaseException(
-          `Link "${ListWrapper.toJSON(linkParams)}" must start with "/", "./", or "../"`);
+      // For a link with no leading `./`, `/`, or `../`, we look for a sibling and child.
+      // If both exist, we throw. Otherwise, we prefer whichever exists.
+      var childRouteExists = this.registry.hasRoute(first, this.hostComponent);
+      var parentRouteExists =
+          isPresent(this.parent) && this.registry.hasRoute(first, this.parent.hostComponent);
+
+      if (parentRouteExists && childRouteExists) {
+        let msg =
+            `Link "${ListWrapper.toJSON(linkParams)}" is ambiguous, use "./" or "../" to disambiguate.`;
+        throw new BaseException(msg);
+      }
+      if (parentRouteExists) {
+        router = this.parent;
+      }
+      rest = linkParams;
     }
 
     if (rest[rest.length - 1] == '') {
@@ -445,7 +458,7 @@ export class Router {
       throw new BaseException(msg);
     }
 
-    // TODO: structural cloning and whatnot
+    var nextInstruction = this.registry.generate(rest, router.hostComponent);
 
     var url = [];
     var parent = router.parent;
@@ -454,8 +467,6 @@ export class Router {
       parent = parent.parent;
     }
 
-    var nextInstruction = this.registry.generate(rest, router.hostComponent);
-
     while (url.length > 0) {
       nextInstruction = url.pop().replaceChild(nextInstruction);
     }

modules/angular2/test/router/integration/router_link_spec.ts

@@ -19,6 +19,7 @@ import {
 
 import {NumberWrapper} from 'angular2/src/core/facade/lang';
 import {PromiseWrapper} from 'angular2/src/core/facade/async';
+import {ListWrapper} from 'angular2/src/core/facade/collection';
 
 import {provide, Component, DirectiveResolver, View} from 'angular2/core';
 
@@ -133,6 +134,58 @@ export function main() {
              });
        }));
 
+    it('should generate link hrefs from a child to its sibling with no leading slash',
+       inject([AsyncTestCompleter], (async) => {
+         compile()
+             .then((_) => router.config([
+               new Route({path: '/page/:number', component: NoPrefixSiblingPageCmp, as: 'Page'})
+             ]))
+             .then((_) => router.navigateByUrl('/page/1'))
+             .then((_) => {
+               rootTC.detectChanges();
+               expect(DOM.getAttribute(rootTC.debugElement.componentViewChildren[1]
+                                           .componentViewChildren[0]
+                                           .nativeElement,
+                                       'href'))
+                   .toEqual('/page/2');
+               async.done();
+             });
+       }));
+
+    it('should generate link hrefs to a child with no leading slash',
+       inject([AsyncTestCompleter], (async) => {
+         compile()
+             .then((_) => router.config([
+               new Route({path: '/book/:title/...', component: NoPrefixBookCmp, as: 'Book'})
+             ]))
+             .then((_) => router.navigateByUrl('/book/1984/page/1'))
+             .then((_) => {
+               rootTC.detectChanges();
+               expect(DOM.getAttribute(rootTC.debugElement.componentViewChildren[1]
+                                           .componentViewChildren[0]
+                                           .nativeElement,
+                                       'href'))
+                   .toEqual('/book/1984/page/100');
+               async.done();
+             });
+       }));
+
+    it('should throw when links without a leading slash are ambiguous',
+       inject([AsyncTestCompleter], (async) => {
+         compile()
+             .then((_) => router.config([
+               new Route({path: '/book/:title/...', component: AmbiguousBookCmp, as: 'Book'})
+             ]))
+             .then((_) => router.navigateByUrl('/book/1984/page/1'))
+             .then((_) => {
+               var link = ListWrapper.toJSON(['Book', {number: 100}]);
+               expect(() => rootTC.detectChanges())
+                   .toThrowErrorWith(
+                       `Link "${link}" is ambiguous, use "./" or "../" to disambiguate.`);
+               async.done();
+             });
+       }));
+
     it('should generate link hrefs when asynchronously loaded',
        inject([AsyncTestCompleter], (async) => {
          compile()
@@ -337,6 +390,21 @@ class SiblingPageCmp {
   }
 }
 
+@Component({selector: 'page-cmp'})
+@View({
+  template:
+      `page #{{pageNumber}} | <a href="hello" [router-link]="[\'Page\', {number: nextPage}]">next</a>`,
+  directives: [RouterLink]
+})
+class NoPrefixSiblingPageCmp {
+  pageNumber: number;
+  nextPage: number;
+  constructor(params: RouteParams) {
+    this.pageNumber = NumberWrapper.parseInt(params.get('number'), 10);
+    this.nextPage = this.pageNumber + 1;
+  }
+}
+
 @Component({selector: 'hello-cmp'})
 @View({template: 'hello'})
 class HelloCmp {
@@ -377,3 +445,27 @@ class BookCmp {
   title: string;
   constructor(params: RouteParams) { this.title = params.get('title'); }
 }
+
+@Component({selector: 'book-cmp'})
+@View({
+  template: `<a href="hello" [router-link]="[\'Page\', {number: 100}]">{{title}}</a> |
+    <router-outlet></router-outlet>`,
+  directives: ROUTER_DIRECTIVES
+})
+@RouteConfig([new Route({path: '/page/:number', component: SiblingPageCmp, as: 'Page'})])
+class NoPrefixBookCmp {
+  title: string;
+  constructor(params: RouteParams) { this.title = params.get('title'); }
+}
+
+@Component({selector: 'book-cmp'})
+@View({
+  template: `<a href="hello" [router-link]="[\'Book\', {number: 100}]">{{title}}</a> |
+    <router-outlet></router-outlet>`,
+  directives: ROUTER_DIRECTIVES
+})
+@RouteConfig([new Route({path: '/page/:number', component: SiblingPageCmp, as: 'Book'})])
+class AmbiguousBookCmp {
+  title: string;
+  constructor(params: RouteParams) { this.title = params.get('title'); }
+}

modules/angular2/test/router/router_spec.ts

@@ -61,7 +61,6 @@ export function main() {
              });
        }));
 
-
     it('should activate viewports and update URL on navigate',
        inject([AsyncTestCompleter], (async) => {
          var outlet = makeDummyOutlet();
@@ -105,7 +104,6 @@ export function main() {
              });
        }));
 
-
     it('should navigate after being configured', inject([AsyncTestCompleter], (async) => {
          var outlet = makeDummyOutlet();
 
@@ -121,14 +119,6 @@ export function main() {
              });
        }));
 
-
-    it('should throw when linkParams does not start with a "/" or "./"', () => {
-      expect(() => router.generate(['FirstCmp', 'SecondCmp']))
-          .toThrowError(
-              `Link "${ListWrapper.toJSON(['FirstCmp', 'SecondCmp'])}" must start with "/", "./", or "../"`);
-    });
-
-
     it('should throw when linkParams does not include a route name', () => {
       expect(() => router.generate(['./']))
           .toThrowError(`Link "${ListWrapper.toJSON(['./'])}" must include a route name.`);