[sharing is fun] example: write and read JSON in javascript

Hey Orange_Glass, thank you so much, you led me on the right path and I think I have a solution. Shell externals made me think of trying out Node, the fs module has tons of useful tricks around files.

For anyone interested, this is how I push and update objects to JSON with Node, which is much more along the right way to do things! The node script is used only to write to the JSON file, it doesn't even read it. In the plain JS file I read and append to the JSON object, which goes into the inlet of the Node script:

//------- nodeScript.js -------- //
const maxApi = require('max-api');
const fs = require('fs'),
path = require('path'),
fileFile = ('writeToJson.json'),
filePath = path.join(__dirname, fileFile);

var newObj = new Object;
var styleValue = 5;

// FUNCTION TO WRITE TO FILE
// two top level key-value pairs are inside the JSON file named "style" and "PARAMS"
maxApi.addHandler('appendParamData', (inletObject) => {
var paramObject = JSON.parse(inletObject); // parse inletObject
newObj.style = styleValue; // create a test object
newObj.PARAMS = paramObject; //append inletObject
// write JSON string to file
fs.writeFile("writeToJson.json", JSON.stringify(newObj), function(err) {
if (err) throw err;
});
});
//------- End Of File -------- //

This is the JS that reads the JSON file and appends dynamic data as needed:

//------- deviceParameters.js -------- //
// (some code ommitted)
// High Level Commands
function writeParams() {
getParamValues2();
writeParamValues();
}

// Get Ableton Parameter Values and create a formatted object
function getParamValues2() {

var paramChunkArray = new Array();
var chosenParam = 0;
var paramValue = null;
numOfParams = device.getcount('parameters');

// create param values object, ex: length = 65
for (chosenParam = 0; chosenParam < numOfParams; chosenParam++) {
paramPath = new LiveAPI('live_set tracks ' + trackNumber + ' devices ' + selectedDevice + ' parameters ' + chosenParam);
paramValue = paramPath.get('value');
paramObject[chosenParam] = paramValue;
}
log("-deviceFunctions: getParamValues2 - paramObject:", paramObject.length, typeof(paramObject), paramObject);

// split param object into chunks of 8, ignoring first number
// note: this will create write function [[ [1],[2],[3] ]]
arrayOfParamValues = (chunk(paramObject, 8));

// create arrays for each group of 8
for (var i = 0; i < arrayOfParamValues.length; i++) {
paramObject[i] = '[' + arrayOfParamValues[i] + ']';
log('paramObject', i, paramObject[i]);
// In this code, JSON.parse makes them arrays and not strings.
paramChunkArray.push(JSON.parse(paramObject[i]));
}
arrayOfParamValues = paramChunkArray;
}

// Chunks function to split an array into segments (to swap portions of an object if needed)
function chunk(arr, len) {
var chunks = [],
i = 1,
n = arr.length;
while (i < n) {
chunks.push(arr.slice(i, i += len));
}
log('chunks');
// log('chunks',chunks,'\n', /*chunks[1], */ typeof(chunks));
return chunks;
}

// Send object through outlet for Node to receive it
function writeParamValues() {
read();
anything(trackNumber, currentClip, arrayOfParamValues);
var jase = JSON.stringify(UI);
outlet(0, jase);
}

// Reads the JSON. ===>MAYBE THE MOST IMPORTANT FUNCTION!!<===
// The last two lines will target a specific key value pair to continually append new data. Check it out suckas.
function read() {
memstr = "";
data = "";
maxchars = 8000;
path = p;
var f = new File(path, "read");
f.open();
if (f.isopen) {
while (f.position < f.eof) {
memstr += f.readstring(maxchars);
}
f.close();
} else {
post("Error\n");
}
// hell yeah
var UIObject = JSON.parse(memstr);
UI = UIObject["PARAMS"];
}

// Appends new data to UI object
function anything()
{ var a = arrayfromargs(arguments);
var id = a[0];
var property = a[1];
var data = a[2];
if (UI == null){UI = new Object();}
if (UI[id] == null) {
UI[id] = new Object();
}
UI[id][property] = data;
}
//------- End Of File #ballin-------- //