为什么我的 await 在我的功能中不起作用？ “语法错误：等待仅在异步函数中有效”

Question

I have a function -

async function run() {
  const drives = await getDrives()
  drives.forEach(function (item) {
    item.size = fileSize(item.size)
    if (item.mountpoints.length > 0) {
      item.path = item.mountpoints[0].path
    } else {
      item.path = 'N/A'
    }

  })

  app.get('/', function (req, res) {
    res.render('record', {
      drives: drives
    })
  });

  app.post('/record', (req, res) => {
    const pExists = pathExists.sync(req.body.path)
    const i = req.body.url
    const test = i.lastIndexOf('/')
    const id = i.substring(test + 1)

    if (i.includes("/album/")) {
      sid = `spotify:album:${id}`
    } else if (i.includes("/playlist/")) {
      sid = `spotify:playlist:${id}`
    } else {
      console.log('failed')
    }

    if (pExists === true) {
      try {
        await myModule.mount(req.body.path, userDetails.path)
        fs.writeFileSync(`${userDetails.path}/diskplayer.contents`, sid)
        res.render('success', {
          path: req.body.path,
          url: req.body.url
        })
      } catch (err) {
        res.render('failed', {
          error: err
        })
      }
    }
  });

And on line 60 I am trying to await for myModule.mount

await myModule.mount(req.body.path, userDetails.path)

But I am getting the error -

await myModule.mount(req.body.path, userDetails.path)
^^^^^

SyntaxError: await is only valid in async function
    at Module._compile (internal/modules/cjs/loader.js:891:18)
    at Object.Module._extensions..js (internal/modules/cjs/loader.js:991:10)
    at Module.load (internal/modules/cjs/loader.js:811:32)
    at Function.Module._load (internal/modules/cjs/loader.js:723:14)
    at Function.Module.runMain (internal/modules/cjs/loader.js:1043:10)
    at internal/main/run_main_module.js:17:11

Though my await on line 27

const drives = await getDrives()

Seems to work fine. I can't seem to work out what I am doing wrong..

Answer 1

您需要将 async 放在这里（在您的回调中）

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

Answer 2

Always whenever you work with Async/Await remember that we can use await only if the promise generating function or task is declared as async function. For using await, make the function in which it is used as async and making the global or parent function async has no effect. So in your case

app.post('/record', async(req, res) => {
....
await myModule.mount(req.body.path, userDetails.path)
....
}

will work.

const drives = await getDrives()

This line is in the run() function and not inside a function in run() function, therefore it works correctly.