如何让 Jest 按预期捕获抛出的错误？

Question

我正在尝试用 Jest 编写一些测试并不断得到以下结果。 如何让 Jest 按预期捕获抛出的错误？ 代码：

test("Test that TEXT_PROPERTIES can throw a typeError", () => {
  function testError() {
    try {
      throw new TypeError(`why doesn't this work`);
    } catch (e) {
      console.error(e);
    }
  }

  expect(() => {
    testError();
  }).toThrow();
});

结果：

  × Test that TEXT_PROPERTIES can throw a typeError (11 ms)

  ● Test that TEXT_PROPERTIES can throw a typeError

    expect(received).toThrow()

    Received function did not throw

      62 |   expect(() => {
      63 |     testError();
    > 64 |   }).toThrow();
         |      ^
      65 | });
      66 | 

      at Object.<anonymous> (tests/components/typography/typography.test.js:64:6)

  console.error
    TypeError: why doesn't this work

我已经阅读了这个问题的许多其他“答案”，但没有一个有效。

Answer 1

testError不会因为 try-catch 块而向外界抛出错误。 从 Jest 的期望来看， testError返回 undefined 而不是异常（错误）。 这是一个类似的测试：

 function testError() { try { throw new TypeError(`why doesn't this work`); } catch (e) { console.error(e); } } var result = testError(); console.log(result); // undefined console.log(result instanceof TypeError); // false

将 function 更改为：

function testError() {
    throw new TypeError(`why doesn't this work`);
}

 function testError() { throw new TypeError(`why doesn't this work`); } // We want to use try-catch to encapsulate the error try { result(); } catch (e){ console.log(e); // undefined console.log(e instanceof TypeError); // false console.log(e instanceof TypeError); // false }