JSON stringify sporadically replaces separator with closing square bracket - node.js

Question

I am running a node.js script that culls through a directory and extracts any regex matches it finds, then pushes them onto an array. Once the query has run, I am stringifying the array into a standalone JSON file for safekeeping until it's needed.
I'm running into sporadic errors where the array in the JSON file is malformed and causes an error when I try to parse it out later on. It is sporadic, and I cannot determine a pattern, but every time (so far) the character that is causing the error is a closing square bracket - just like the one between the 2nd and 3rd elements below:
["first string","second string"]"third string"]
It's almost as if my array.push() is just adding another element onto the end of the existing array, and "forgetting" to change the closing square bracket to a comma...
I have searched, but cannot find references to a known error that would cause this. Has anyone seen this before?
Environment:
Node.js v19.0.0 | Ubuntu 22.04.1 LTS | Intel i7 processor
Here's my code for generating the JSON files:
const fs = require('fs');
const path = require('path');
const devPath = '/home/user/directory';
const activeReminder = [];
function buildArray() {
let getFiles = fs.readdirSync(devPath);
getFiles.forEach(file => {
splitMD(file);
});
}
function splitMD(file) {
if (path.extname(file) == ".md" & file != {}) {
let data = fs.readFileSync(file, 'utf8');
const line = data.split(/\r?\n/);
const match = line.find(element => {
extractions(element, file);
});
}
};
function extractions(element, file) {
if (element.includes("- [ ] reminder: ")) { //the - [ ] is markdown for Obsidian
const datedReminder = "- [ ] [["+file+"]]" + element.split('- [ ] reminder:')[1]
activeReminder.push(datedReminder);
buildReminderJSON();
}
}
function buildCcioJSON() {
const reminderJSON = JSON.stringify(activeReminder);
fs.writeFile("reminder.json", reminderJSON, 'utf8', function (err) {
if (err) {
console.log("Error while writing CCIO JSON:");
return console.log(err);
}
})
}
buildArray();
module.exports = { buildArray };

Answer 1

I don't know what's causing the anomaly described above, but I created a script to correct it as a workaround until I can figure out a root cause. I'm running it as a crontab a few minutes after the crontab that creates the original array.
const fs = require('fs')
const path = require('path')
const devPath = '/home/user/directory'
function cleanup() {
let getFiles = fs.readdirSync(devPath);
getFiles.forEach(file => {
splitJSON(file);
});
}
function splitJSON(file) {
if (path.extname(file) == ".json" & file != {}) {
let data = fs.readFileSync(file, 'utf8');
const line = data.split(/\r?\n/);
const match = line.find(element => {
jsonCheck(element, file);
});
}
};
function jsonCheck(element, file) {
if (element.includes("\"]\"")) {
fs.readFile(file, 'utf8', function (err,data) {
if (err) {
return console.log(err);
}
var result = data.replace(/\"\]\"/g, '","');
fs.writeFile(file, result, 'utf8', function (err) {
if (err) return console.log(err);
});
});
}
}
cleanup();
module.exports = { cleanup };