如何讓 Jest 按預期捕獲拋出的錯誤？

Question

我正在嘗試用 Jest 編寫一些測試並不斷得到以下結果。 如何讓 Jest 按預期捕獲拋出的錯誤？ 代碼：

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();
});

結果：

  × 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

我已經閱讀了這個問題的許多其他“答案”，但沒有一個有效。

Answer 1

testError不會因為 try-catch 塊而向外界拋出錯誤。 從 Jest 的期望來看， testError返回 undefined 而不是異常（錯誤）。 這是一個類似的測試：

 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

將 function 更改為：

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 }