调用 controller function 与 promise 无法等待，然后 ZC1C425268E68385D1AB50741C

Question

I have a function in a controller that wants to create two different models if a condition is satisfied in the data base. The API gets called:

PUT localhost:3000/user

calls app.post('/user', user.create)

the user.create is in a controller file:

const business = require("./controllers/business.controller.js");

exports.create = (req,res) => {

    const user = new User ({
    email: req.body.email
    uniqueAccount: req.body.unique
    })

    User.create (user, function(err,doc){
        if (err) res.status(500).send(err)
        if (user.uniqueAccount) {
            let result = business.create(req,res)
            console.log(result)
        }

        res.send(doc)
    })
}

in the business controller, it is the same function:

exports.create = (req,res) => {
    const business = new Business({
        name: req.body.businessname
    })

    Business.create (business, function(err,doc){
        if (err) return err
        return doc
    }
}

because my of the line:

let result = business.create(req,res) has no promise await, I am not able to see return from the business controller. I tried using a.then function but I come accross the error:

TypeError: Cannot read property 'then' of undefined

How do I properly go about this? I could just import the model into my user controller, and then create the business model in the user controller but I wanted to separate the purposes.

Answer 1

You can use await on a function only if it returns a promise, so return a promise from your business controller instead of returning a simple value.

You can promisify your business controller function and then use await inside your user.create function. Do it like this:

     const business = require("./controllers/business.controller.js");

     exports.create = (req,res) => {

        const user = new User ({
        email: req.body.email
        uniqueAccount: req.body.unique
     })

     User.create (user, async function(err,doc){
       if (err) res.status(500).send(err)
       if (user.uniqueAccount) {
         let result = await business.create(req,res)
         console.log(result)
       }

       res.send(doc)
      })
    }

Now promisify your business controller function.

      exports.create = (req,res) => {
        return new Promise((resolve,reject)=>{
          const business = new Business({
            name: req.body.businessname
          })

          Business.create (business, function(err,doc){
             if (err) reject(err)
             resolve(doc)
          }
        });
      }