catcherror-spec.ts

import { jest } from '@jest/globals';
import '../iterablehelpers';
import { first, from, of, range, sequenceEqual, single, throwError } from 'ix/iterable/index.js';
import { catchError } from 'ix/iterable/operators/index.js';

test('Iterable#catchError error catches', () => {
  const err = new Error();
  const res = single(
    throwError(err).pipe(
      catchError((e: Error) => {
        expect(e).toEqual(err);
        return of(42);
      })
    )
  );
  expect(42).toBe(res);
});

test('Iterable#catchError no error misses', () => {
  const xs = range(0, 10);
  const res = xs.pipe(catchError((_: Error) => of(42)));
  expect(sequenceEqual(res, xs)).toBeTruthy();
});

test('Iterable#catchError source and handler types are composed', () => {
  const xs = range(0, 10);
  const res = xs.pipe(catchError((_: Error) => of('foo')));
  expect(sequenceEqual(res, xs)).toBeTruthy();
});

test('Iterable#catchError calls return() on source iterator when stopped early', () => {
  const xs = range(0, 10)[Symbol.iterator]();
  const returnSpy = jest.spyOn(xs, 'return');

  const res = from(xs).pipe(catchError((_: Error) => from([])));

  first(res);

  expect(returnSpy).toHaveBeenCalled();
});