Question

exports.createTour = async (req, res) => {
  try {
    const newTour = await Tour.create(req.body);
    res.status(201).json({
      status: "success",
      data: {
        tours: newTour,
      },
    });
  } catch (err) {
    res.status(400).json({
      status: "fail",
      message: err,
    });
  }
};

一切都在运行，直到我在这里添加了异步功能。这可能是什么原因？

Answer 1

Tour.create内部发生了什么？

难道您是在Promise.reject()内部调用new Promise((resolve,reject){...})而不是使用reject()？

下面的代码在我的“ bla”函数中同时拒绝和解决案件：

exports.createTour = async (req, res) => {
      try {
        const newTour = await bla();
        res.status(201).json({
          status: "success",
          data: {
            tours: newTour,
          },
        });
      } catch (err) {
        res.status(400).json({
          status: "fail",
          message: err,
        });
      }
});

    
    let bla=()=>{
      return new Promise((resolve, reject)=>{
        //resolve("yay");
        reject("I have my reasons");
      });
    }

我将尽力解释我所怀疑的情况- 但是如果不看代码就很难知道：

let create = ()=>{
      // option 1. returns a new promise that resolves - your catch should work 
      Promise.resolve("great success");

      return new Promise((resolve, reject)=>{
        // option 2. creates a new promise in the new promise, which would explain the situation you described
        Promise.reject("I need to be handled too - but im not");

        // option 3. handles the locally created and rejected promise
        Promise.reject("I need to be handled too").catch(x => console.log("handled"));

        // option 4. rejects and is caught in the createTour function that called us - your catch should work  
        reject("I have my reasons");

       // option 5. another function you call rejects and is not handled - would also cause what you described, for the same reason
       let result = await func();
      });
    }

尝试查看您是否正在执行某种选择5或2-它会在诺言中创建一个诺言，该诺言会拒绝（并且不会被处理）。

另外，请注意，您可以在代码中使用完整的try {..} catch {..}代替

await Tour.create().catch(err => ...);

（类似于选项2）并专门处理拒绝

如果您想了解更多信息： https://blog.bitsrc.io/6-ways-to-implement-a-promise-in-javascript-9238aec9c17b

我的NodeJ给出了unhandledPromise错误

1 个答案: