Question

据我所知，两个对象failApiClient和explicitFailApiClient应该具有相同的类型，并且记录它们似乎同意：

console.log(failApiClient) // { getObjects: [Function: getObjects] } console.log(explicitFailApiClient) // { getObjects: [Function: getObjects] }

阅读this问题会给我正确处理此问题所需的信息，但并不能告诉我为什么生成的failApiClient会导致警告，而{{1 }} 才不是。

我已将其削减到接近重新创建情况并演示替代方法所需的最低水平：

explicitFailApiClient

import * as sinon from 'sinon'; import 'source-map-support/register'; class LocalObject { } const fakeObject = new LocalObject(); const getFakeApi = (result: Promise<LocalObject[]>) = ({getObjects: () => result}); const successObjectClient = getFakeApi(Promise.resolve([fakeObject])); // These should be equivalent, but the former causes a test error const failApiClient = getFakeApi(Promise.reject(new Error())); const explicitFailApiClient = { getObjects(): Promise<LocalObject[]> { return Promise.reject(new Error()); } }; describe('successApiClient', () => { before(() => { sinon.spy(successObjectClient, 'getObjects'); }); it('does not have a warning', async () => { // do nothing }); }); describe('failApiClient', () => { before(() => { sinon.spy(failApiClient, 'getObjects'); }); it('should not have a warning', async () => { // do nothing }); }); describe('explicitFailApiClient', () => { before(() => { sinon.spy(explicitFailApiClient, 'getObjects'); }); it('does not have a warning', async () => { // do nothing }); });的结果：

~/...> tsc && npm test

Answer 1

它们不是等效的。

在下面的代码中，当JS作为语句的参数Promise.reject时，它已经执行了，这就是为什么您得到预警UnhandledPromiseRejectionWarning的原因。

const failApiClient = getFakeApi(Promise.reject(new Error()));

与

相比

const explicitFailApiClient = {
  getObjects(): Promise<LocalObject[]> {
    return Promise.reject(new Error());
  }
};

调用Promise.reject时将评估其explicitFailApiClient.getObjects()的

。

解决方案

这是我针对此问题的替代解决方案。我可以只使用Sinon的resolves和rejects。

const getFakeApi = {getObjects: (result) => result};
const getFakeApiStub = sinon.stub(getFakeApi, 'getObjects');

describe('successApiClient', () => {
  before(() => {
    getFakeApiStub.resolves([fakeObject]); // success and resolves
  });

  it('does not have a warning', async () => {
    // do nothing
  });

});

describe('failApiClient', () => {
  before(() => {
    getFakeApiStub.rejects(new Error()); // make it failed
  });

  it('should not have a warning', async () => {
    // do nothing
  });
});

参考： https://sinonjs.org/releases/v6.3.5/stubs/#stubresolvesvalue

希望有帮助

Answer 2

承诺可能无法解决，解决或拒绝。 “ then”用于处理分辨率，而“ catch”则用于拒绝。您抛出的拒绝没有被抓住。

尝试SomePromiseRejection().catch(err => DoSomeStuff(err))

因此，在调用explicitFailApiClient之后，有一个.catch块。

使用sinon时出现不一致的UnhandledPromiseRejectionWarning

2 个答案:

解决方案