jasmine - Jasmine的toBe匹配器是否支持传第二个参数？

Question

我从 Angular 的文档中找到了这个代码片段，但无法从 Jasmine 的文档中找到这个用法。这真的是受支持的功能吗？我只是想确保如果我使用此功能，它不会在升级到较新的次要/补丁版本时意外中断。

expect(masterService.getValue())
.toBe(stubValue, 'service returned stub value');

Answer 1

jasmine.Matchers.toBe 的第二个可选参数(名为 expectationFailOutput)是当 expect 失败时显示的消息。无论是否出现在Jasmine documentation , 它确实受支持并存在于 jasmine.Matchers 接口(interface)的大多数方法中。

interface Matchers {
    ...
    toBe(expected: any, expectationFailOutput?: any): boolean;
    toEqual(expected: any, expectationFailOutput?: any): boolean;
    toMatch(expected: string | RegExp, expectationFailOutput?: any): boolean;
    toBeDefined(expectationFailOutput?: any): boolean;
    toBeUndefined(expectationFailOutput?: any): boolean;
    toBeNull(expectationFailOutput?: any): boolean;
    ...
    toBeTruthy(expectationFailOutput?: any): boolean;
    toBeFalsy(expectationFailOutput?: any): boolean;
    ...
    toContain(expected: any, expectationFailOutput?: any): boolean;
    toBeLessThan(expected: number, expectationFailOutput?: any): boolean;
    toBeLessThanOrEqual(expected: number, expectationFailOutput?: any): boolean;
    toBeGreaterThan(expected: number, expectationFailOutput?: any): boolean;
    toBeGreaterThanOrEqual(expected: number, expectationFailOutput?: any): boolean;
    toBeCloseTo(expected: number, precision?: any, expectationFailOutput?: any): boolean;