This is my code:

let newArray = []
const myProcess = (id) => {
  // after 5 seconds, add id to newArray
}

router.use('/', async (req, res) => {
  myProcess(req.query.id);
  if (newArray.includes(req.query.id) {
    res.send({})
  }
}

But this code not work for me

I want to send {} after add id to newArray

CodePudding user response：

To fix this, you can use the await keyword to wait for the myProcess function to finish before checking if the newArray array includes the id. example;

let newArray = []
const myProcess = (id) => {
  // after 5 seconds, add id to newArray
  setTimeout(() => {
    newArray.push(id)
  }, 5000)
}

router.use('/', async (req, res) => {
  await myProcess(req.query.id);
  if (newArray.includes(req.query.id) {
    res.send({})
  }
}

CodePudding user response：

You've said:

• myProcess will add an ID to the array after five seconds
• you don't want to send the {} until the ID has been added

That means that your code won't respond to the request for / for five seconds, which is a long time in "I'm waiting for something" terms. :-) Just to flag that up.

But to do it, have myProcess return a promise it fulfills once it's added the ID to the array, then wait for that promise to settle before sending the response:

let newArray = [];
const myProcess = (id) => {
    return new Promise((resolve, reject) => {
        // after 5 seconds, add id to newArray and call
        // `resolve` (or call `reject` if something
        // goes wrong)
    });
};

router.use("/", async (req, res) => {
    myProcess(req.query.id)
        .then(() => {
            if (newArray.includes(req.query.id)) {
                res.send({});
            } else {
                // ...send something else...
            }
        })
        .catch((error) => {
            // ...send an error reply...
        });
});