Using Node.JS, how do I read a JSON file into (server) memory?

04/10/2020 08:00:01

Background

I am doing some experimentation with Node.js and would like to read a JSON object, either from a text file or a .js file (which is better??) into memory so that I can access that object quickly from code. I realize that there are things like Mongo, Alfred, etc out there, but that is not what I need right now.

Question

How do I read a JSON object out of a text or js file and into server memory using JavaScript/Node?

Verified Answer (1164 Votes)

04/04/2012 17:27:19

Sync:

var fs = require('fs');
var obj = JSON.parse(fs.readFileSync('file', 'utf8'));

Async:

var fs = require('fs');
var obj;
fs.readFile('file', 'utf8', function (err, data) {
  if (err) throw err;
  obj = JSON.parse(data);
});
1164

Answer #2 (385 Votes)

10/19/2014 07:14:04

The easiest way I have found to do this is to just use require and the path to your JSON file.

For example, suppose you have the following JSON file.

test.json

{
  "firstName": "Joe",
  "lastName": "Smith"
}

You can then easily load this in your node.js application using require

var config = require('./test.json');
console.log(config.firstName + ' ' + config.lastName);
385

Answer #3 (56 Votes)

04/04/2012 17:33:10

Asynchronous is there for a reason! Throws stone at @mihai

Otherwise, here is the code he used with the asynchronous version:

// Declare variables
var fs = require('fs'),
    obj

// Read the file and send to the callback
fs.readFile('path/to/file', handleFile)

// Write the callback function
function handleFile(err, data) {
    if (err) throw err
    obj = JSON.parse(data)
    // You can now play with your datas
}
56
3
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