Using async when two requests have to be made and response from the first is needed in the other req-CodePudding

I have a async function like this:

exports.myFunction = async (req, res, next) => {
  if (some condition) {
     next()
  }

  try {

    const results = await axios.get(`https://a-domain.com/url/path`);
    const info = results.data;

    const docRef = await addDoc(collection(db, "name_of_collec"), info);
    console.log("Document written with ID: ", docRef.id);
  } catch (e) {
    console.error("Error adding document: ", e);
  }

  next();
};

Here, response from the first request is required in the second request. But according to my knowledge since I am making asynchronous requests, the two requests should be made at the same time.

What I cannot understand:

So, how it is possible that there is no error occurring?
How is it that, sometimes the no document is added to Firestore? Like it is skipped somehow...

Context info:

I am using Express.js and Node.js to make a backend
I am using axios to make the first request and the second one is adding a document to Firestore.
Firestore is a noSQL database inside Google's Firebase.

CodePudding user response：

But according to my knowledge since I am making asynchronous requests, the two requests should be made at the same time.

asynchronous doesn't mean that the requests are made at the same time. It means the code won't wait for the responses from these requests. Requests are made in the manner you add them in the code and responses will be asynchronous i.e the response will be received at some point in future time.

And there is no guarantee in what manner they will be received.

So, how it is possible that there is no error occurring?

It is not necessary that the error occurs when you request. If that is the case catch handler should be activated.

How is it that, sometimes the no document is added to Firestore? Like it is skipped somehow...

The reason might be info is an empty object and firestore automatically removes the empty document.

CodePudding user response：

Use await keywords where you want the code to wait for result.

const result = await request1;
const result2 = await request2(request1.data);