异步诺言不返回结果

Question

How come I do not get a value in my res after the promise resolves?

My console.log looks something like this:

=====!!USER NOT FOUND!!=====
Res: undefined

This is my function

async function findUser(userID, userType) {
    await new Promise((resolve, reject) => {
    usersTable.findOne (
        { _id: userID }
    ,function (err, data) {
        if (err) {
            throw new Error('findUser: ' + err);
        } else {
            if (!data) {
                console.log("=====!!USER NOT FOUND!!=====")
                resolve("NEW");
            } else {
                console.log("=====USER FOUND=====")
                resolve("OK");
            };
        };
    });
})};

This is my caller

async function main() {
    var res = "";
    try { 

        // Find the user
        res = await findUser(userEmail, "tenant");
        console.log("Res: " + res );
        if (res == "NEW") {
            res = await newUser();                  // Add the new tenant
        }
    }
    catch(err) {
        console.error(err);
        console.log(" newBooking: " + err);
        callback( { error:true, err } );
    }
}
main();

Answer 1

find User should return sth:

async function findUser(userID, userType) {
   return await new Promise((resolve, reject) => {
   ...
   });
}

If you do await findUser() youre waiting until the async function returns sth. Your async function returns undefined.

---

By the way: You might not use an async function at all:

function findUser(userId,userType){
  return new Promise(...);
}