Factorio BluePrint String Parser in NodeJS

bp_parse.js

var input = `H4sIAAAAAAAA/42R0WrDMAxFfyX0OYImg74Uf0vxbK0V2HImOWHD5N/ndKOsacn2FAjn5lzd+NSE5G
xoTqYgZ8qEakphG9HsrCrG10B8hmjdhRih37VD0oolNuXDwEv7afbz3P4kNFrJQKwoGWXFdle29STo
ri8Pt1xIZ9JMDtwFNcNQzTQhDJIm8usP7e+df7dclYzoaYyAodaQ6hxSwPvA0hS6/531cFV/i71Z3R
yjex5bjSH4PtbnsxV+VdxwPagONUYu8fKniT0uyMaW1fFN9ZvUPB8F8yjcnI7I/gvQdo5aWgIAAA==`;

var crypto = require("crypto");
var zlib = require("zlib");

var LuaVMJS = require('lua.vm.js');

// create our luaVM for re-use
var luaVM = new LuaVMJS.Lua.State();
// load our modified JSON lib that pushes JSON to global scope
luaVM.execute(require("fs").readFileSync(__dirname + "/json.lua", "utf-8"));

function Decode(str) {
    return new Promise(function(resolve, reject) {
        zlib.unzip(Buffer.from(str, 'base64'), (err, buffer) => {
            if (!err) {
                return resolve(buffer.toString());
            } else {
                // handle error
                reject(err);
            }
        });
    });
}

function Parse(str) {
    return new Promise(function(resolve, reject) {
        // create variable name we want lua to inject into
        var injectVar = "factorio_bp_" + RandomString(64);

        // turn Blueprint string into a function
        // TODO - OMG HOW DO I CHECK THIS IS SAFE TO DO???
        luaVM.execute(`
        function export_bp_${injectVar}()
        ${str}
        end`);
        
        // inject LUA table as JSON into JS global variable
        luaVM.execute(`
        js.global.${injectVar} = JSON:encode(export_bp_${injectVar}())
        `);

        // return a JSON parsed version of the injected string
        resolve(JSON.parse(global[injectVar]));

        // remove export_bp_${injectvar} function
        luaVM.execute(`
        export_bp_${injectVar} = nil
        `);

        // delete from the JS global scope too to clear up memory
        delete global[injectVar];
    });
}

// generate a random string for lua->js variable injection
function RandomString(len)
{
    return crypto.randomBytes(len).toString('hex');
}

Decode(input).then(Parse).then(function(data) {
    console.log(JSON.stringify(data, null, 2));
}, console.error);