How To Parse JSON in Node.js

    RahulBy 2 Mins ReadUpdated:

    JSON, or JavaScript Object Notation, is a lightweight data-interchange format that is easy for humans to read and write. Node.js has built-in support for parsing JSON files, making it a breeze to work with JSON data. To parse a JSON file in Node.js, you can use the built-in JSON module. The JSON module provides an efficient way to parse and stringify JSON data. It also provides a number of helpful methods for working with JSON data.

    This tutorial will help you to read JSON file using Node.js uses readFile and readFileSync functions of the jsonfile module.

    Installing Node Module

    For this tutorial, we are using jsonfile npm module. So first you need to install jsonfile module on your system

    npm install jsonfile --save

    Next create a sample json file for running few examples. You can use your own json file.

    nano employee.json

    Add the follwoing snippte:

    [
  {
    "emp_id" : "101",
    "emp_name" : "Mike",
    "emp_addr" : "123 California, USA",
    "designation" : "Editor"
  },
  {
    "emp_id" : "102",
    "emp_name" : "Jacob",
    "emp_addr" : "456 Log Angelis, USA",
    "designation" : "Chief Editor"
  }
]

    Save file content and close it.

    Next, we will run a few examples to read JSON file created above.

    Option #1: Read JSON File with Nodejs

    In the above step, I have created a sample JSON file. Now create ReadJsonFile.js and add the following content. You need to change employee.json with your JSON file name.

    Filename: ReadJsonFile.js

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    var jsonFile = require('jsonfile')
    var fileName = 'employee.json'
     
    jsonFile.readFile(fileName, function(err, jsonData) {
      if (err) throw err;
      for (var i = 0; i < jsonData.length; ++i) {
     
        console.log("Emp ID: "+jsonData[i].emp_id);
        console.log("Emp Name: "+jsonData[i].emp_name);
        console.log("Emp Address: "+jsonData[i].emp_addr);
        console.log("Designation: "+jsonData[i].designation);
        console.log("----------------------------------");
      }
    });

    Now run the nodejs script using following command.

    node ReadJsonFile.js 

Emp ID: 101
Emp Name: Mike
Emp Address: 123 California, USA
Designation: Editor
----------------------------------
Emp ID: 102
Emp Name: Jacob
Emp Address: 456 Log Angelis, USA
Designation: Chief Editor
----------------------------------

    Option #2: Read JSON File (readFileSync)

    Alternatively, you can use readFileSync function to read json file content. Create a ReadJsonFileSync.js file with following content. You can read here about the differences of readFile and readFileSync function in Jode.js.

    Filename: ReadJsonFileSync.js

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    var jsonFile = require('jsonfile')
    var fileName = 'employee.json'
     
    var jsonData = jsonFile.readFileSync(fileName);
     
    for (var i = 0; i < jsonData.length; ++i) {
     
    console.log("Emp ID : "+jsonData[i].emp_id);
    console.log("Emp Name : "+jsonData[i].emp_name);
    console.log("Emp Address : "+jsonData[i].emp_addr);
    console.log("Designation : "+jsonData[i].designation);
    console.log("----------------------------------");
    }

    Now run the nodejs script using following command.

    node ReadJsonFileSync.js 

Emp ID: 101
Emp Name: Mike
Emp Address: 123 California, USA
Designation: Editor
----------------------------------
Emp ID: 102
Emp Name: Jacob
Emp Address: 456 Log Angelis, USA
Designation: Chief Editor
----------------------------------
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    3 Comments

    3. sarika on

      Thanks for this post! I’m still a learner on this technology,this info seems to be really helpful. Thanks again!

      Reply

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