How to parse JSON using Node.js? [closed]

Answer 1

use the JSON object:

JSON.parse(str);

Answer 2

Parsing a JSON stream? Use JSONStream.

var request = require('request')
  , JSONStream = require('JSONStream')

request({url: 'http://isaacs.couchone.com/registry/_all_docs'})
    .pipe(JSONStream.parse('rows.*'))
    .pipe(es.mapSync(function (data) {
      return data
    }))

https://github.com/dominictarr/JSONStream

Answer 3

Just to make this as complicated as possible, and bring in as many packages as possible...

const fs = require('fs');
const bluebird = require('bluebird');
const _ = require('lodash');
const readTextFile = _.partial(bluebird.promisify(fs.readFile), _, {encoding:'utf8',flag:'r'});
const readJsonFile = filename => readTextFile(filename).then(JSON.parse);

This lets you do:

var dataPromise = readJsonFile("foo.json");
dataPromise.then(console.log);

Or if you're using async/await:

let data = await readJsonFile("foo.json");

The advantage over just using readFileSync is that your Node server can process other requests while the file is being read off disk.

Answer 4

Just want to complete the answer (as I struggled with it for a while), want to show how to access the json information, this example shows accessing Json Array:

var request = require('request');
request('https://server/run?oper=get_groups_joined_by_user_id&user_id=5111298845048832', function (error, response, body) {
  if (!error && response.statusCode == 200) {
    var jsonArr = JSON.parse(body);
    console.log(jsonArr);
    console.log("group id:" + jsonArr[0].id);
  }
})

Answer 5

If you need to parse JSON with Node.js in a secure way (aka: the user can input data, or a public API) I would suggest using secure-json-parse.

The usage is like the default JSON.parse but it will protect your code from:

• prototype poisoning
• and constructor abuse:

const badJson = '{ "a": 5, "b": 6, "__proto__": { "x": 7 }, "constructor": {"prototype": {"bar": "baz"} } }'

const infected = JSON.parse(badJson)
console.log(infected.x) // print undefined

const x = Object.assign({}, infected)
console.log(x.x) // print 7

const sjson = require('secure-json-parse')
console.log(sjson.parse(badJson)) // it will throw by default, you can ignore malicious data also

Answer 6

Include the node-fs library.

var fs = require("fs");
var file = JSON.parse(fs.readFileSync("./PATH/data.json", "utf8"));

For more info on 'fs' library , refer the documentation at http://nodejs.org/api/fs.html