Co executes the generator function, how to return data after multiple co functions have been returned?

let form = new multiparty.Form({
                encoding: "utf-8",
                // uploadDir:"public/upload",  //
                keepExtensions: true  //
            })
            form.parse(ctx.req, function (err, fields, files) {
                let data=[]
                for(let f of files.file){
                    // 
                    let date = new Date()
                    let time = "" + date.getFullYear() + (date.getMonth() + 1) + date.getDate()
                    let filepath = "project/"+time + "/" + date.getTime()
                    let fileext = f.originalFilename.split(".").pop()
                    let upfile = f.path
                    let newfile = filepath + "." + fileext
                    //ali-oss
                    co(function*() {
                        client.useBucket("p-adm-test")
                        let result = yield client.put(newfile, upfile)
                        console.log("!", result.url)
                        data.push(result.url)
                        console.log(data)
                        resolve()
                    }).catch(function(err) {
                        console.log(err)
                    })
                }
                ctx.response.type = "json"
                ctx.response.body = {
                    errno: 0,
                    data: data
                }
            })

as in the above code, I have executed the co function many times. I hope that the result returned each time will be push to the data array, and the data returned to the front end will be the data, after multiple execution, but what if the front end only receives the data, returned for the first time?

var arr = [] for(let f of files.file){ arr.push(fn(newfile,upfile)) } //Promise.all(arr,function(res){ Promise.all(arr.then(function(res){ ctx.response.body = { errno: 0, data: res } })

form.parse(ctx.req, co.warp(function* (err, fields, files) { let data = [] for(let f of files.file){ let res = yield fn(newfile,upfile) data.push(res) } ctx.response.body = { errno: 0, data: data } }))