Where should i put async and await?

Question

Where should i put async and await? result is work2 work1

app.post('/upload', (req, res) => {
    const txtupload = multer().any()
    let validate = true
    txtupload(req,res, (err)=>{
        console.log('work1')
        validate = false
    })

    if(validate){
        console.log('work2')
        //code
    }
});

Answer 1

The upload function from multer doesn't return a promise, so async / await isn't applicable. Instead, issue your response in the callback.

Your real question seems to be: How do I use multer to handle file uploads? For that we go to the multer documentation . Adapting that documentation to your code:

app.post('/upload', (req, res) => {
    const txtupload = multer().any();
    txtupload(req,res, (err) => {
        if (err) {
            // ...it failed, send a failure response via `res`...
        } else {
            // ...it worked, send a success response via `res`...
        }
    });
    // Don't do anything here, the upload hasn't been processed yet
});

But refer to the examples in the documentation, there are other patterns for using multer .

Answer 2

因为它是一个箭头函数，所以你必须把它放在参数之前：

app.post('/upload', async (req, res) => { ... }