如何使用 angular 2/4 的鼠标滚轮事件测试指令 [英] How to test a directive with a mouse wheel event in angular 2 / 4

问题描述

我有一个带有鼠标滚轮事件的指令，它用于放大和缩小画布.我想知道如何为这样的事件编写单元测试.我在网上找不到任何例子，有人能指出我正确的方向吗?

我的指令:

import { Directive, ElementRef, HostListener} from "@angular/core";从./my-service"导入 { MyService };@指示({选择器:[testDirec]"})导出类测试{私有 initPointX:数字；私人 initPointY:数字；构造函数(私有元素:ElementRef，私人服务实例:MyService) {}@HostListener('鼠标滚轮', ['$event'])滚动(事件:鼠标事件){console.log("输入鼠标滚轮");let wheelDelta = Math.max(-1, Math.min(1, (event.wheelDelta || -event.detail)));如果(wheelDelta > 0){因子 = 0.5；}别的 {因子 = 2.0；}this.initPointX = event.PageX;this.initPointY = event.PageY;}}

解决方案

您应该使用转换并测试它.如下

<input type="text" value=""/>
@指示({选择器:'[滚动]'})导出类 ChangeDirective{我:数字=1；构造函数(私人渲染器:渲染器，私人 el: ElementRef){}@HostListener('mousewheel', ['$event']) onMousewheel(event) {if(event.wheelDelta>0){event.srcElement.style.setProperty('transition','all 200ms 缓入')event.srcElement.style.setProperty('transform',"scale(" + this.i+1 +")")}if(event.wheelDelta<0){event.srcElement.style.setProperty('transition','all 200ms 缓出')event.srcElement.style.setProperty('transform',"scale(" + this.i-1 +")")}}}

现场演示

I have a directive which has a mouse wheel event, it is used to zoom in and out a canvas. I would like to know how can I write a unit test for such an event. I couldn't find any example online, could anyone point me in a right direction?

My directive:

import { Directive, ElementRef, HostListener} from "@angular/core";
import { MyService } from "./my-service";
@Directive({
    selector: "[testDirec]"
})
export class Test {
  private initPointX: number;
  private initPointY: number;

  constructor(private ele: ElementRef,
        private serviceInstance: MyService) {
    }

    @HostListener('mousewheel', ['$event'])
    scroll(event: MouseEvent) {
        console.log("Entered mouse wheel");
        let wheelDelta = Math.max(-1, Math.min(1, (event.wheelDelta || -event.detail)));
        if(wheelDelta > 0) {
          factor = 0.5;
        }else {
         factor = 2.0;
        }

        this.initPointX = event.PageX;
        this.initPointY = event.PageY;   
    } 

}

解决方案

You should be using transform and test it. as below

<div scrollstyle="height:1000px;background-color:red">
      <input type="text" value=""/>
</div>



@Directive({
    selector: '[scroll]'
})
export class ChangeDirective{
 i:number=1;
    constructor(
        private renderer: Renderer,
        private el: ElementRef
    ){}

    @HostListener('mousewheel', ['$event']) onMousewheel(event) {
      if(event.wheelDelta>0){
          event.srcElement.style.setProperty('transition','all 200ms ease-in')
          event.srcElement.style.setProperty('transform',"scale(" + this.i+1 +")")
      }
      if(event.wheelDelta<0){
        event.srcElement.style.setProperty('transition','all 200ms ease-out')
        event.srcElement.style.setProperty('transform',"scale(" + this.i-1 +")")
      }
    }
}

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