Node.js 中的异步循环

Question

 async function bald(fileName) { try { let aPayload = ''; let aStream = fs.createReadStream(`./tmp/${fileName}`, 'utf8'); aStream.on('data', (chunk) => { aPayload += chunk; }).on('end', async () => { let aJson = JSON.parse(aPayload); for await (let a of aJson) { console.log(a.id); console.log("Tick"); await dbItems.findOne({id: a.id}, (err, result) => { console.log("Something Should Happen;"); }); } }); } catch (e) { throw e; } }

In this answer is content I wanted to try: https://stackoverflow.com/a/50874507/12640130

I found out that forEach won't work at all so I changed it to for... of, but it doesn't make a difference for me. Can somebody find out what's my problem?

Current output:

ID
Tick
ID
Tick
ID
Tick
// ... and so on.
Something Should Happen!
Something Should Happen!
Something Should Happen!
// ... and so on.

Expected output:

ID
Tick
Something Should Happen!
ID
Tick
Something Should Happen!
ID
Tick
Something Should Happen!
// ... and so on.

Answer 1

You can't use await and callbacks at the same time. it should be one of the following:

1. this will not wait for result before iterating.

                    dbItems.findOne({id: a.id}, (err, result) => {
                        console.log("Something Should Happen!");
                    });

2. supposed to be what you're looking for.

                    const result = await dbItems.findOne({id: a.id})
                    console.log("Something Should Happen!");