node.js - JS的异步问题

Question

如图想在reqst函数内部返回body的内容，求指教～

Answer 1

callback

Answer 2

(err,res,body)=>{} is a callback, right?
It should be written like this

(err,res)=>{
        if(err){
        throw err
        }else{
        return (
        //对res进行操作
        )
        }
    }

res should be the data returned by the background. I don’t know the format, so I can only write an idea.

Answer 3

// callback
function rqst(callback) {
    request({}, (err, res, body) => {
        if (err) return callback(err);
        callback(null, body);
    })
}

rqst(function(err, body) {
    // body
})

// promise
function rqst() {
    return new Promise(resolve, reject) => {
        request({}, (err, res, body) => {
            if (err) reject(err);
            resolve(body)
        })
    }
}

rqst.then(body => {
    // body
}).catch(e => {
})