fix(aio): correctly intercept links with LinkDirective

aio/src/app/shared/link.directive.spec.ts

@@ -1,7 +1,93 @@
+import { async, inject, ComponentFixture, TestBed } from '@angular/core/testing';
+import { By } from '@angular/platform-browser';
+import { Component } from '@angular/core';
+import { LocationService } from 'app/shared/location.service';
+import { MockLocationService } from 'testing/location.service';
 import { LinkDirective } from './link.directive';
 
-xdescribe('LinkDirective', () => {
-  it('should attach to all anchor elements', () => {});
-  it('should bind a property to the "href" attribute', () => {});
-  it('should intercept clicks on the element and call `location.go()`', () => {});
+describe('LinkDirective', () => {
+
+  @Component({
+    template: '<a href="{{ url }}">Test Link</a>'
+  })
+  class TestComponent {
+    url: string;
+  }
+
+  beforeEach(async(() => {
+    TestBed.configureTestingModule({
+      declarations: [
+        LinkDirective,
+        TestComponent
+      ],
+      providers: [
+        { provide: LocationService, useFactory: () => new MockLocationService('initial/url') }
+      ]
+    })
+    .compileComponents();
+  }));
+
+  it('should attach to all anchor elements', () => {
+    const fixture = TestBed.createComponent(TestComponent);
+    const directiveElement = fixture.debugElement.query(By.directive(LinkDirective));
+    expect(directiveElement.name).toEqual('a');
+  });
+
+  it('should bind a property to the "href" attribute', () => {
+    const fixture = TestBed.createComponent(TestComponent);
+    const directiveElement = fixture.debugElement.query(By.directive(LinkDirective));
+
+    fixture.componentInstance.url = 'test/url';
+    fixture.detectChanges();
+    expect(directiveElement.properties['href']).toEqual('test/url');
+  });
+
+  it('should set the "target" attribute to "_blank" if the href is absolute, otherwise "_self"', () => {
+    const fixture = TestBed.createComponent(TestComponent);
+    const directiveElement = fixture.debugElement.query(By.directive(LinkDirective));
+
+    fixture.componentInstance.url = 'http://test/url';
+    fixture.detectChanges();
+    expect(directiveElement.properties['target']).toEqual('_blank');
+
+    fixture.componentInstance.url = 'https://test/url';
+    fixture.detectChanges();
+    expect(directiveElement.properties['target']).toEqual('_blank');
+
+    fixture.componentInstance.url = 'ftp://test/url';
+    fixture.detectChanges();
+    expect(directiveElement.properties['target']).toEqual('_blank');
+
+    fixture.componentInstance.url = '//test/url';
+    fixture.detectChanges();
+    expect(directiveElement.properties['target']).toEqual('_blank');
+
+    fixture.componentInstance.url = 'test/url';
+    fixture.detectChanges();
+    expect(directiveElement.properties['target']).toEqual('_self');
+
+    fixture.componentInstance.url = '/test/url';
+    fixture.detectChanges();
+    expect(directiveElement.properties['target']).toEqual('_self');
+  });
+
+  it('should intercept clicks for local urls and call `location.go()`', inject([LocationService], (location: LocationService) => {
+    const fixture = TestBed.createComponent(TestComponent);
+    const directiveElement = fixture.debugElement.query(By.directive(LinkDirective));
+    fixture.componentInstance.url = 'some/local/url';
+    fixture.detectChanges();
+    location.go = jasmine.createSpy('Location.go');
+    directiveElement.triggerEventHandler('click', null);
+    expect(location.go).toHaveBeenCalledWith('some/local/url');
+  }));
+
+  it('should not intercept clicks for absolute urls', inject([LocationService], (location: LocationService) => {
+    const fixture = TestBed.createComponent(TestComponent);
+    const directiveElement = fixture.debugElement.query(By.directive(LinkDirective));
+    fixture.componentInstance.url = 'https://some/absolute/url';
+    fixture.detectChanges();
+    location.go = jasmine.createSpy('Location.go');
+    directiveElement.triggerEventHandler('click', null);
+    expect(location.go).not.toHaveBeenCalled();
+  }));
 });

aio/src/app/shared/link.directive.ts

@@ -1,10 +1,10 @@
-import { Directive, HostListener, HostBinding, Input } from '@angular/core';
+import { Directive, HostListener, HostBinding, Input, OnChanges } from '@angular/core';
 import { LocationService } from 'app/shared/location.service';
 @Directive({
   /* tslint:disable-next-line:directive-selector */
   selector: 'a[href]'
 })
-export class LinkDirective {
+export class LinkDirective implements OnChanges {
 
   // We need both these decorators to ensure that we can access
   // the href programmatically, and that it appears as a real
@@ -13,11 +13,27 @@ export class LinkDirective {
   @HostBinding()
   href: string;
 
+  @HostBinding()
+  target: string;
+
   @HostListener('click', ['$event'])
   onClick($event) {
+    if (this.isAbsolute(this.href)) {
+      return true;
+    } else {
       this.location.go(this.href);
       return false;
     }
+  }
+
+  private isAbsolute(url) {
+    return /^[a-z]+:\/\/|\/\//i.test(url);
+  }
 
   constructor(private location: LocationService) { }
+
+  ngOnChanges() {
+    this.target = this.isAbsolute(this.href) ? '_blank' : '_self';
+  }
+
 }