How can I parse through local JSON file in React js?

Question

How can I parse through a JSON file retrieving all its data and using it in my code?

I've tried importing the file and just tried console logging it, but all it does is print Object {}:

import jsonData from "./file.json";
console.log(jsonData);

This is what my file.json looks like:

[
    {
      "id": 1,
      "gender": "Female",
      "first_name": "Helen",
      "last_name": "Nguyen",
      "email": "hnguyen0@bloomberg.com",
      "ip_address": "227.211.25.18"
    }, {
      "id": 2,
      "gender": "Male",
      "first_name": "Carlos",
      "last_name": "Fowler",
      "email": "cfowler1@gnu.org",
      "ip_address": "214.248.201.11"
    }
]

I'd want to be able to access the first and last name of each component and print those on the website.

this seemed to work for me as is – steff_bdh Sep 10 '19 at 03:49 — steff_bdh, Sep 10 '19 at 03:49

gotnull · Accepted Answer · 2020-08-25T08:03:56.010

var data = require('../../file.json'); // forward slashes will depend on the file location

var data = [
    {
      "id": 1,
      "gender": "Female",
      "first_name": "Helen",
      "last_name": "Nguyen",
      "email": "hnguyen0@bloomberg.com",
      "ip_address": "227.211.25.18"
    }, {
      "id": 2,
      "gender": "Male",
      "first_name": "Carlos",
      "last_name": "Fowler",
      "email": "cfowler1@gnu.org",
      "ip_address": "214.248.201.11"
    }
];

for (var i = 0; i < data.length; i++)
{
    var obj = data[i];
    console.log(`Name: ${obj.last_name}, ${obj.first_name}`);
}

https://jsfiddle.net/c9wupvo6/

I am getting this error: `Uncaught Error: Cannot find module "json!./Sections/file.json"` even though that is the right path. — Parkicism, Jun 06 '16 at 13:05

score 19 · Answer 2 · answered Aug 04 '18 at 00:37

Applications packaged with webpack 2.0.0+ (such as those created with create-react-app) support imports from json exactly as in the question (see this answer.

Be aware that import caches the result, even if that result is parsed json, so if you modify that object, other modules that also import it have references to the same object, not a newly parsed copy.

To get a "clean" copy, you can make a function that clones it such as:

import jsonData from './file.json';

const loadData = () => JSON.parse(JSON.stringify(jsonData));

Or if you're using lodash:

import jsonData from './file.json';
import { cloneDeep } from 'lodash';

const loadData = () => cloneDeep(jsonData);

you need to put that json file inside src folder. – novato Jan 13 '23 at 10:15 — novato, Jan 13 '23 at 10:15

score 17 · Answer 3 · answered Sep 28 '16 at 16:09

17

I also had problems with getting an empty Object back. Even when using require as suggested above.

fetch however solved my problem:

fetch('./data/fakeData.json')
  .then((res) => res.json())
  .then((data) => {
    console.log('data:', data);
  })

(As of today, the support isn't optimal though: http://caniuse.com/#feat=fetch)

answered Sep 28 '16 at 16:09

patad

9,364
11
38
44

32

This seems like it should work. But whenever I try it I get "localhost/:1 Uncaught (in promise) SyntaxError: Unexpected token < in JSON at position 0" – PlunkettBoy Jul 25 '17 at 20:16
how to make this work? the url generated for the fetch is incorrect. hence the jseals. error. – Community Feb 07 '20 at 08:26
2

@Community I've found a solution! Instead of passing the relative path, you need to pass the complete path(inside your project), like `fetch("src/data/fakeData.json)`. Instead of using `res.json()`, use `res.text()`, and, in the last then, use `JSON.parse(data)` – reisdev Feb 13 '20 at 12:25
1

Thanks Muchachito - its getting there - just DONT FORGET to wrap this inside a useEffect or it wont work & also loop forever while failing – Sagive Oct 20 '22 at 00:20

score 4 · Answer 4 · answered Jun 06 '16 at 19:58

For those of you who also have trouble with this, this code seemed to have fixed the problem

var jsonData = require('../../file.json');

class blah extends React.Component {

render(){
    var data; 

    function loadJSON(jsonfile, callback) {   

        var jsonObj = new XMLHttpRequest();
        jsonObj.overrideMimeType("application/json");
        jsonObj.open('GET', "../../file.json", true);
        jsonObj.onreadystatechange = function () {
              if (jsonObj.readyState == 4 && jsonObj.status == "200") {
                callback(jsonObj.responseText);
              }
        };
        jsonObj.send(null);  
     }

    function load() {

        loadJSON(jsonData, function(response) {
            data = JSON.parse(response);
            console.log(data);
        });
    }

    load();
}

}

This seems excessive for getting JSON into a local JS code, isn't there an easier solution? — Shazam, Jan 07 '17 at 05:18

score 2 · Answer 5 · answered Mar 20 '20 at 15:55

2

The JS spread operator also helps to get a deep copy of the object.

import jsonData from '../../file.json';

const loadData = [...jsonData];

answered Mar 20 '20 at 15:55

fireflycaptainz

53
4

2

The spread operator is a SHALLOW copy, not a deep one. The above would result in a new array, but the exact same object instances within it. – Eric Haynes Feb 14 '21 at 02:51
@EricHaynes is right – thodwris Nov 29 '21 at 22:39

How can I parse through local JSON file in React js?

5 Answers5

Linked