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.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 | 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.
1 2 3 4 5 6 7 8 9 10 11 12 13 | 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 ----------------------------------
3 Comments
How can we break this down further and create routes to pull only what we want from the .json file?
Very helpful information for learners like me, I would thankful for this blog.
Thanks for this post! I’m still a learner on this technology,this info seems to be really helpful. Thanks again!