返回空 Observable 时不调用订阅回调

Question

我希望在返回空 Observable 时调用 subscribe 回调，类似于 Promise.resolve([]):

import { EMPTY } from 'rxjs';

function funcToTest(): Observable<any[]> {
  return EMPTY;
};

test('returns empty array', (done) => {
  funcToTest().subscribe(() => {
    done();
  });
});

相反，它 returns 这个错误：

Error: Timeout - Async function did not complete within 5000ms (set by jasmine.DEFAULT_TIMEOUT_INTERVAL)

Answer 1

Observable 的行为与 promise 不同。 RxJS EMPTY Observable 不调用 'success' 回调，只调用 'complete' 回调。 done 函数应该在 'complete' 中调用，而不是在 'success' 中调用：

funcToTest().subscribe({
  success()  { /* Called when 'x' is returned, e.g. after the subscriber calls 'next' */ },
  error(err) { /* Called on an error. */ },
  complete() {
    /* Called after the subscriber calls 'complete'. No more values can be returned */
    done();
  }
});

查看文档中的示例：https://rxjs-dev.firebaseapp.com/guide/observable

返回空 Observable 时不调用订阅回调

Subscribe callback not called when empty Observable returned

javascript

jasmine

rxjs