在 NodeJS 中引发错误 - UnhandledPromiseRejection

Question

我对 NodeJS 还很陌生，我仍在试图弄清楚如何处理错误。我读了很多问题，但我不知道我做错了什么。

这里我有一个登录功能：

export const login = async (req, res) => {

let body = req.body;

try {

  const user = await User.findOne({ username: body.username });

if (!user) {

  throw new InternalError("Username or password are wrong");

}

if (!bcrypt.compareSync(body.password, user.password)) {

  throw new InternalError("Username or password are wrong");

}

let token = jwt.sign({ data: user }, "secret", {

  expiresIn: 60 * 60 * 24 * 30

});

return res.json({

  user: user,

  token: token

 });

} catch (error) {

throw new GenericError(error);

 }

};

这是我得到的错误，例如，我包含错误的密码：

(node:12332) UnhandledPromiseRejectionWarning: GenericError: Username or password are wrong

(node:12332) UnhandledPromiseRejectionWarning: Unhandled promise rejection. This error originated either by 

throwing inside of an async function without a catch block, or by rejecting a promise which was not handled with .catch()

我知道用 Await 做出的承诺必须有一个.then()and.catch()但这不是执行承诺时的错误，而是验证密码时的错误。我想要的是抛出错误并获得响应。现在请求永远不会结束，并且会显示上一个错误。

Answer 1

您收到来自节点的警告，因为您在捕获 InternalError 后重新抛出了 GenericError。与其重新抛出 GenericError，不如在调用时返回响应或捕获 GenericError login。这是您为两者修改的代码。export const login = async (req, res) => {  // We get the body info  let body = req.body;  try {    // We find the user with the username from the body    const user = await User.findOne({ username: body.username });    // Let's assume no user exists, so we throw an InternalError,    // This skips straight to the catch block.    if (!user) {      throw new InternalError("Username or password are wrong");    }    // We never reach these two statements    // because of the error above being thrown.    if (!bcrypt.compareSync(body.password, user.password)) {      throw new InternalError("Username or password are wrong");    }    let token = jwt.sign({ data: user }, "secret", {      expiresIn: 60 * 60 * 24 * 30    });   res.json({      user: user,      token: token    });  } catch (err) {    // We caught our InternalError from not having a user above.    // Now we should return a response that the user is invalid.    // I am just going to return the error that we previously threw.   res.json({      error: err    });  }};您绝对可以从 catch 块中抛出 GenericError。但是，这样做需要您在调用登录函数的任何地方捕获 GenericError。export const login = async (req, res) => {  // We get the body info  let body = req.body;  try {    // We find the user with the username from the body    const user = await User.findOne({ username: body.username });    // Let's assume no user exists, so we throw an InternalError,    // This skips straight to the catch block.    if (!user) {      throw new InternalError("Username or password are wrong");    }    // We never reach these two statements    // because of the error above being thrown.    if (!bcrypt.compareSync(body.password, user.password)) {      throw new InternalError("Username or password are wrong");    }    let token = jwt.sign({ data: user }, "secret", {      expiresIn: 60 * 60 * 24 * 30    });   res.json({      user: user,      token: token    });  } catch (err) {    // Throw the generic error    throw GenericError(err);  }};try {  // We call the login function that is defined above.  // It is going to throw a GenericError, so we have to  // catch it.  await login(req, res);} catch (err) {  // Now we need to catch the generic error  res.json({    error: err  });}