Angular 4管单元测试不适用于基本管道

Question

Angular 4管单元测试不适用于基本管道

业力错误我得到：typeError：无法读取未定义的

的属性'0'

这是我的管道（非常基本）：

import { Pipe, PipeTransform } from "@angular/core";
@Pipe({
  name: "userPipe",
  pure: true
})
export class MyFilter implements PipeTransform {
   transform(items: any, [listOfItems]: any) {
     // Example of a pipe: listOfItems = listOfItems.filter(item => item.type === "test");
     return listOfItems;
  }
}

这是我的管道单位测试：

import { MyFilter } from "./user.pipe";
describe("userPipe", () => {
  let pipe: MyFilter;
  let fakeResponse = ["abc"];
  beforeEach(() => {
    pipe = new MyFilter();
  });
  it("transforms abc to abc", () => {
    expect(pipe.transform(fakeResponse)).toEqual(fakeResponse);
  });
});

Answer 1

首先更新您的变换功能，测试将使用此代码

export class MyFilter implements PipeTransform {
   transform( items: Array<any> ) {
     return listOfItems;
  }
}