How can I parse through local JSON file in React j

问题:

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": "[e-mail]",
      "ip_address": "227.211.25.18"
    }, {
      "id": 2,
      "gender": "Male",
      "first_name": "Carlos",
      "last_name": "Fowler",
      "email": "[e-mail]",
      "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.

回答1:

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": "[e-mail]",
      "ip_address": "227.211.25.18"
    }, {
      "id": 2,
      "gender": "Male",
      "first_name": "Carlos",
      "last_name": "Fowler",
      "email": "[e-mail]",
      "ip_address": "214.248.201.11"
    }
];

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

https://jsfiddle.net/c9wupvo6/

回答2:

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)

回答3:

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);

回答4:

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();
}

}