Returning the response from fetch to the function which called it

Question

I have a code something like this:

function getData(query){
    fetch('some-url').then((res)=>res.json())
    .then((res)=>{
      return 'string'+res.data
    })

The above function is

var data = getData('text');

I want the getData function to return modified string to store it in the variable data. How do I achieve this?

Not an export in promises, but what if you tried `return fetch('some-url').then((res)=>res.json()) .then((res)=>{ return 'string'+res.data })` — Nick Parsons, Dec 26 '18 at 12:26
Possible duplicate of [How do I return the response from an asynchronous call?](https://stackoverflow.com/questions/14220321/how-do-i-return-the-response-from-an-asynchronous-call) — Dmitry, Dec 26 '18 at 12:27

score 0 · Accepted Answer · answered Dec 26 '18 at 12:27

function getData(query){
    return  fetch('some-url').then((res)=>res.json())
    .then((res)=>{
      return 'string'+res.data
    })

and call it like

    getData('text').then(function(res){
       //your code should be here 
       var data=res;
    });

score 0 · Answer 2 · answered Dec 26 '18 at 12:29

0

You can use async/await to achieve the desired result

function getData(query){
    return fetch('some-url').then((res)=>res.json())
    .then((res)=>{
      return 'string'+res.data
    })

Then:

var data = await getData('text'); //You will get your modified string in the data.

answered Dec 26 '18 at 12:29

Harish Soni

1,796
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2

It says 'await is only valid in async function' – Chirag Dec 26 '18 at 12:34
You have marked Ahmed's answer as answer, does it solved your poblem? – Harish Soni Dec 26 '18 at 13:52
Yes Harish, it does – Chirag Dec 26 '18 at 14:04

score 0 · Answer 3 · answered Dec 26 '18 at 12:34

fetch is a Promise, and you can change data only in .then method after fetch returned your data.

fetch('some-url')
    .then((res) => res.json()) 
    .then((res) => 'string'+res.data)
    .then((res) => /* some code */) // in this string you can achieve data.

Returning the response from fetch to the function which called it

3 Answers3