Is it possible to modify an array located on a JSON file?

Question

I'm attempting to make a command that will store an array of strings, and because I don't like to do have the chance of losing everything due to the process restarting, I've decided to use a JSON file array. So far, I've been able to write to the file and add array. However, my roadblock is attempting to modify that array and have the file update with it. Whenever I attempt to .push to the array, it does add the string, just not to the file. So I pose the question: Is it possible to modify an array, located in a JSON file? Snippets of code are below

const database = require('../../characters.json')

const charArray = database[message.author.id]
switch(args[0].toLowerCase()) {
  case "add":
    charArray.push(`${args.slice(1).join(" ")}`)
    break;
  case "view":
    // This code works
  case "remove":
    let pos = charArray.indexOf(`${args.slice(1).join(" ")}`)
    charArray.splice(pos, 1)
    break;
  default:
    // This code works
}

I think you should write the changes to the file https://stackoverflow.com/questions/36856232/write-add-data-in-json-file-using-node-js — Izzy Engelbert, Nov 23 '20 at 03:14
@IzzyEngelbert I believe that is the basis of Harshana Smith's answer — Coder Tavi, Nov 23 '20 at 19:02

score 2 · Accepted Answer · answered Nov 23 '20 at 03:15

You have to write into the JSON file in order to modify the array inside it. For that, you can use NodeJS fs library. Check the code below:

const fs = require('fs');
const database = require('../../characters.json')

const charArray = database[message.author.id]
switch(args[0].toLowerCase()) {
  case "add":
    charArray.push(`${args.slice(1).join(" ")}`)
    database[message.author.id] = charArray;
    fs.writeFileSync('../../characters.json', JSON.stringify(database));
    break;
  case "view":
    // This code works
  case "remove":
    let pos = charArray.indexOf(`${args.slice(1).join(" ")}`)
    charArray.splice(pos, 1)
    break;
  default:
    // This code works
}

I assume for `remove`, I do the same fs.writeFileSync code? – Coder Tavi Nov 23 '20 at 10:00 — Coder Tavi, Nov 23 '20 at 10:00

score 0 · Answer 2 · answered Nov 23 '20 at 03:14

0

You will have to rewrite your whole json file everytime you do a mutation.

answered Nov 23 '20 at 03:14

kigiri

2,952
21
23

Is it possible to modify an array located on a JSON file?

2 Answers2