How do I properly implement the map function with fetch API in React?

Question

I'm trying to insert the data fetched into a map function that returns each employe's name in

, but im getting an error that says "data.map is not a function". How can I fix this>

import React, { useState, useEffect } from "react";

//const data = [{id:1,employee_name:"Tiger Nixon",employee_salary:320800,employee_age:61,profile_image:""},{id:2,employee_name:"Garrett Winters",employee_salary:170750,employee_age:63,profile_image:""}]

export default function App() {
 const [data, setData] = useState([]);
  useEffect(() => {
    fetch("https://dummy.restapiexample.com/api/v1/employees")
      .then(response => response.json())
      .then(result => setData(result))
  },[]);
  const information = data.map((item,i) => {
    return (<h1> item.employee_name </h1>);

  })
  return (
    <div className="App">
      <h1> {information} </h1>
      <h2>Start editing to see some magic happen!</h2>
    </div>
  );
}

Have you tried printing data to see what it actually is when the error prints? — tkausl
– tkausl, Commented Oct 6, 2021 at 0:48
console.log(data) returns this: [] {status: "success", data: Array(24), message: "Successfully! All records has been fetched."} status: "success" data: Array(24) message: "Successfully! All records has been fetched." — youngprogrammer1997
– youngprogrammer1997, Commented Oct 6, 2021 at 0:51

Lith · Accepted Answer · 2021-10-06 01:31:25Z

Open the link https://dummy.restapiexample.com/api/v1/employees (where u fetching data)

Notice that it returns an Object NOT an array. the object contains status (a string), data (array) and message (string). The data is the part u wish to save. Right now you are saving the entire object hence .map is not a function.

There are 2 ways to fix it.

1st save ONLY the data into ur state

  useEffect(() => {
    fetch("https://dummy.restapiexample.com/api/v1/employees")
      .then(response => response.json())
      .then(result => setData(result.data || []))
  },[]);

NOTE adding [] ensures that if data is a null - the array would exist hence .map would not throw an error.

OR switching ur state model to an object const [data, setData] = useState(null); and rendering like so

  const information = data?.data?.map((item,i) => {
    return (<h1> item.employee_name </h1>);
  })

NOTE using ?. is just an IF that if it dosent exist. If data? has value of .data. and ?.map if the .data has a method .map. If any of these return false - entire thing returns a null.

Would recommend sticking with the 1st way. But up to you

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