Javascript – Add object to json file – Node.js


I'm trying to add an object to a very large JSON file in Node.js (but only if the id doesn't match an existing object). What I have so far:

example JSON file:

    text: "some text"
    text: "some other text"


var fs = require('fs');     
var jf = require('jsonfile')
var util = require('util')    
var file = 'example.json'

// Example new object
var newThing = {
  id: 324,
  text: 'more text'

// Read the file
jf.readFile(file, function(err, obj) {
  // Loop through all the objects in the array
  for (i=0;i < obj.length; i++) {
    // Check each id against the newThing
    if (obj[i].id !== {
      found = false;
      console.log('thing ' + obj[i].id + ' is different. keep going.');
    }else if (obj[i].id =={
      found = true;
      console.log('found it. stopping.');
  // if we can't find it, append it to the file
    console.log('could not find it so adding it...');
    fs.appendFile(file, ', ' + JSON.stringify(newTweet) + ']', function (err) {
      if (err) throw err;

This is so close to what I want. The only problem is the trailing ] character at the end of the JSON file. Is there a way to delete it using the file system API or something? Or is there a much easier way to do exactly what I want?

Best Solution

The proper way to handle this is to parse the JSON file, modify the object, and output it again.

var obj = require('file.json');
obj.newThing = 'thing!';
fs.writeFile('file.json', JSON.stringify(obj), function (err) {