Use data returned from API call outside of Promise.then() function

Question

I am very puzzled on a relatively trivial question.

I wish to retrieve data from my database using a node.js API call, the API call is working perfectly fine, and I am able to successfully retrieve data in my.then(()=>{}) function in my promise.

However the issue I am having is that I wish to use this data outside of the scope of the "then" particularly I want to map the results into a ListViewItem in my front end.

Here is the code

    import {Box, Button, Grid, List, ListItem, ListItemButton, ListItemText} from "@mui/material"
import {useEffect} from "react";
import axios from "axios";

  function RequestApproval() {

      let dataFromDb =[]

      const result =  axios.get("http://localhost:3001/all-user-addresses").then((response) => {
          console.log(response.data.result); //This works perfectly fine 
          dataFromDb.concat(response.data.result)
      })

      console.log(dataFromDb) //This list always appears empty.
      const data = result;



    return (
        <div style={{display: 'flex', justifyContent: 'center', alignItems: 'center', height: '100vh'}}>
            <Box style={{borderRadius: '16px', backgroundColor: '#6ea6be'}}>
                <List sx={{width: '600px', maxWidth: '1000px'}}>
                    {//My listview items from my API call go over here
                    }
                </List>
            </Box>
        </div>

    );
}



export default RequestApproval;

Answer 1

you need to use state for this problem. at first

const [list,setList]= useState([])

then in your RequestApproval function replace

dataFromDb.concat(response.data.result)

by this

setList(response.data.result)

and your jsx map through the list array.

Answer 2

You can simply utilize the useState hook.

Replace let dataFromDb =[] with const [data, setData] = useState() . Then instead of using dataFromDb.concat(response.data.result) use setData(response.data.result) .

For more information look at the official docs