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

我已经阅读了很多关于这个问题的其他“答案”，但 none 其中有效。

Answer 1

testError 不会因为 try-catch 块而向外界抛出错误。从 Jest 的 expect 来看，testError returns undefined 而不是异常（error）。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

将函数改成这样：

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
}

如何让 Jest 按预期捕获抛出的错误？

How do I get Jest to catch the thrown error as expected?

javascript

try-catch

throw

jestjs