angular-docs-cn/packages/platform-browser/test/dom/events/hammer_gestures_spec.ts

/**
 * @license
 * Copyright Google LLC All Rights Reserved.
 *
 * Use of this source code is governed by an MIT-style license that can be
 * found in the LICENSE file at https://angular.io/license
 */
import {NgZone} from '@angular/core';
import {fakeAsync, inject, tick} from '@angular/core/testing';
import {afterEach, beforeEach, describe, expect, it,} from '@angular/core/testing/src/testing_internal';
import {EventManager} from '@angular/platform-browser';
import {HammerGestureConfig, HammerGesturesPlugin,} from '@angular/platform-browser/src/dom/events/hammer_gestures';

{
  describe('HammerGesturesPlugin', () => {
    let plugin: HammerGesturesPlugin;
    let fakeConsole: any;
    if (isNode) return;

    beforeEach(() => {
      fakeConsole = {warn: jasmine.createSpy('console.warn')};
    });

    describe('with no custom loader', () => {
      beforeEach(() => {
        plugin = new HammerGesturesPlugin(document, new HammerGestureConfig(), fakeConsole);
      });

      it('should implement addGlobalEventListener', () => {
        spyOn(plugin, 'addEventListener').and.callFake(() => () => {});

        expect(() => {
          plugin.addGlobalEventListener('document', 'swipe', () => {});
        }).not.toThrowError();
      });

      it('should warn user and do nothing when Hammer.js not loaded', () => {
        expect(plugin.supports('swipe')).toBe(false);
        expect(fakeConsole.warn)
            .toHaveBeenCalledWith(
                `The "swipe" event cannot be bound because Hammer.JS is not ` +
                `loaded and no custom loader has been specified.`);
      });
    });

    describe('with a custom loader', () => {
      // Use a fake custom loader for tests, with helper functions to resolve or reject.
      let loader: () => Promise<void>;
      let resolveLoader: () => void;
      let failLoader: () => void;

      // Arbitrary element and listener for testing.
      let someElement: HTMLDivElement;
      let someListener: () => void;

      // Keep track of whatever value is in `window.Hammer` before the test so it can be
      // restored afterwards so that this test doesn't care whether Hammer is actually loaded.
      let originalHammerGlobal: any;

      // Fake Hammer instance ("mc") used to test the underlying event registration.
      let fakeHammerInstance: {on: () => void, off: () => void};

      // Inject the NgZone so that we can make it available to the plugin through a fake
      // EventManager.
      let ngZone: NgZone;
      beforeEach(inject([NgZone], (z: NgZone) => {
        ngZone = z;
      }));

      let loaderCalled = 0;

      beforeEach(() => {
        originalHammerGlobal = (window as any).Hammer;
        (window as any).Hammer = undefined;

        fakeHammerInstance = {
          on: jasmine.createSpy('mc.on'),
          off: jasmine.createSpy('mc.off'),
        };

        loader = () => {
          loaderCalled++;
          return new Promise((resolve, reject) => {
            resolveLoader = resolve;
            failLoader = reject;
          });
        };

        // Make the hammer config return a fake hammer instance
        const hammerConfig = new HammerGestureConfig();
        spyOn(hammerConfig, 'buildHammer').and.returnValue(fakeHammerInstance);

        plugin = new HammerGesturesPlugin(document, hammerConfig, fakeConsole, loader);

        // Use a fake EventManager that has access to the NgZone.
        plugin.manager = {getZone: () => ngZone} as EventManager;

        someElement = document.createElement('div');
        someListener = () => {};
      });

      afterEach(() => {
        loaderCalled = 0;
        (window as any).Hammer = originalHammerGlobal;
      });

      it('should call the loader provider only once', () => {
        plugin.addEventListener(someElement, 'swipe', () => {});
        plugin.addEventListener(someElement, 'panleft', () => {});
        plugin.addEventListener(someElement, 'panright', () => {});
        // Ensure that the loader is called only once, because previouly
        // it was called the same number of times as `addEventListener` was called.
        expect(loaderCalled).toEqual(1);
      });

      it('should not log a warning when HammerJS is not loaded', () => {
        plugin.addEventListener(someElement, 'swipe', () => {});
        expect(fakeConsole.warn).not.toHaveBeenCalled();
      });

      it('should defer registering an event until Hammer is loaded', fakeAsync(() => {
           plugin.addEventListener(someElement, 'swipe', someListener);
           expect(fakeHammerInstance.on).not.toHaveBeenCalled();

           (window as any).Hammer = {};
           resolveLoader();
           tick();

           expect(fakeHammerInstance.on).toHaveBeenCalledWith('swipe', jasmine.any(Function));
         }));

      it('should cancel registration if an event is removed before being added', fakeAsync(() => {
           const deregister = plugin.addEventListener(someElement, 'swipe', someListener);
           deregister();

           (window as any).Hammer = {};
           resolveLoader();
           tick();

           expect(fakeHammerInstance.on).not.toHaveBeenCalled();
         }));

      it('should remove a listener after Hammer is loaded', fakeAsync(() => {
           const removeListener = plugin.addEventListener(someElement, 'swipe', someListener);

           (window as any).Hammer = {};
           resolveLoader();
           tick();

           removeListener();
           expect(fakeHammerInstance.off).toHaveBeenCalledWith('swipe', jasmine.any(Function));
         }));

      it('should log a warning when the loader fails', fakeAsync(() => {
           plugin.addEventListener(someElement, 'swipe', () => {});
           failLoader();
           tick();

           expect(fakeConsole.warn)
               .toHaveBeenCalledWith(
                   `The "swipe" event cannot be bound because the custom Hammer.JS loader failed.`);
         }));

      it('should load a warning if the loader resolves and Hammer is not present', fakeAsync(() => {
           plugin.addEventListener(someElement, 'swipe', () => {});
           resolveLoader();
           tick();

           expect(fakeConsole.warn)
               .toHaveBeenCalledWith(
                   `The custom HAMMER_LOADER completed, but Hammer.JS is not present.`);
         }));
    });
  });
}