angular - Jasmine 单元测试：如何访问由 @input() 设置的属性？使用 component.propertyname 访问它会返回 undefined

Question

ts文件：

@input() selectedDep: WebMessagingDeployments[]

规格文件：

beforeEach(() => {

    fixture = TestBed.createComponent(DeploymentAssignmentFormComponent);
    component = fixture.componentInstance;
    
    console.log(component.selectedDep) // returns undefined
    component.selectedDep.push(mockDepData); //this line throws error. TypeError: Cannot read property '0' of undefined
}));  

标签： angularkarma-jasmine

Answer 1

看起来您尚未selectedDep在组件或测试文件中初始化。

几个选项是：

1. 声明时初始化

   @Input() selectedDep: WebMessagingDeployments[] = [];

2. 在测试中初始化

   夹具 = TestBed.createComponent(DeploymentAssignmentFormComponent); 组件=fixture.componentInstance；component.selectedDep = [/* 这里的值 */]; 夹具.detectChanges();