TypeScript compile error: Array.map(callback) expression is not callable

Question

Following is a Node.js API written in Typescript,

app.post('/photos/upload', upload.array('photos', 12), async (req, res) => {
  var response = { }
  var list = []
  try {
    const col = await loadCollection(COLLECTION_NAME, db)

    var myfiles = req.files
    console.log("myfiles", myfiles);
    myfiles.map( function(item, index) {

                //return checkExisting(col, item)
    })
}}

and getting the following typescript error at the line myfiles.map(function(item, index) {

index.ts:77:13 - error TS2349: This expression is not callable.
  Not all constituents of type 'File[] | (<U>(callbackfn: (value: File, index: number, array: File[]) => U, thisArg?: any) => U[])' are callable.
    Type 'File[]' has no call signatures.

77     myfiles.map( function(item, index) {
               ~~~

As I am completely new to Typescript, not sure, what is the problem, myfiles.map(callback) is a valid callable method on an array so why typescript reports not callbale.

Before the error line put: console.log (typeof myfiles) and type the result here — Aks Jacoves
– Aks Jacoves, Commented Jun 8, 2020 at 16:14
the key would be to see what checkExisting does. Take a look at this. stackoverflow.com/a/51573837/17447 — codeandcloud
– codeandcloud, Commented Jun 8, 2020 at 16:17
@naveen Already disabled checkExisting and tried but same error. checkExisting a function — b Tech
– b Tech, Commented Jun 8, 2020 at 16:18
@AksJacoves It's a typescripts compile time error so console.log is not executed. I tried it. Moreover I see in the terminal npm ERR! [email protected] prestart: tsc`` and Failed at the [email protected] prestart script. — b Tech
– b Tech, Commented Jun 8, 2020 at 16:22

Alessio · Accepted Answer · 2020-10-17 09:12:38Z

1

I'm not sure why that happens, but you can try this:

var myfiles = JSON.parse(JSON.stringify(req.files))

It would look something like this:

app.post('/photos/upload', upload.array('photos', 12), async (req, res) => {
    var response = { }
    var list = []
    try {
        const col = await loadCollection(COLLECTION_NAME, db)

        var myfiles = JSON.parse(JSON.stringify(req.files))
        console.log("myfiles", myfiles);
        myfiles.map( function(item, index) {

            //return checkExisting(col, item)
        })
    }}

edited Oct 17, 2020 at 9:12

Alessio

3,70620 gold badges42 silver badges52 bronze badges

answered Oct 17, 2020 at 4:20

Luis D.S

112 bronze badges

Sign up to request clarification or add additional context in comments.

Collectives™ on Stack Overflow

TypeScript compile error: Array.map(callback) expression is not callable

1 Answer 1

Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related