使用Jest在角度中使用.find方法对数组进行单元测试 [英] Unit test for array with .find method in angular using jest

问题描述

如何使用.find方法以角度获取数组的覆盖率.我在下面的代码段遇到了麻烦.

How to get coverage for array with .find method in angular. I'm getting trouble in the below piece of code.

sample.component.ts

sample.component.ts

public permissions = [{id: 0, value: 'fruit' }, {id: 1, value: 'vegetable'}];
this.filteredList = this.permissions.slice();
public isFiltered(permission) {
    return this.filteredList.find(item => item.id === permission.id);
}

sample.spec.ts

sample.spec.ts

it('should call myMethod ', () => {
  expect(component.isFiltered(1)).toEqual(true);
});

我遇到以下错误， TypeError: Cannot read property 'find' of undefined

任何帮助将不胜感激

推荐答案

像这样写

 it('should call myMethod ', () => {
   let permissions = [{id: 0, value: 'fruit' },{id: 1, value: 'vegetable'} ];
   component.filteredList = permissions.slice();
   expect(component.isFiltered({id:1}).value).toEqual('vegetable');
 });

您需要为component.filteredList

更新

在ts中使用persmissions.id进行过滤时，需要将具有属性id的对象(进行过滤)传递给isFiltered().同样，isFiltered不会返回布尔值，而是对象(即搜索结果本身)，因此我们将其值检查为必需的

as you are using persmissions.id in your ts to filter you need to pass an object with property id(to filter by) to isFiltered(). Also isFiltered does not returns a boolean but the object (i.e. search result itself) so we check its value to be the required one

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