Convert some Lua tables to JS objects

luaToJSON.js

/*
 * A quick and dirty script to convert SOME lua tables to JSON objects
 *
 * This is NOT an attempt at a comprehensive Lua table converter.  It
 * will catch ones that I encountered a lot in my coding of tabletop
 * simulator scripts specifically.  I used this to scale and adjust
 * hard-coded snap points and other data quickly so I wouldn't have to
 * do it by hand
 */

const fs = require('fs')
const JSONC = require('comment-json')

// Read lua from file and attempt to convert
const luaStr = fs.readFileSync('./luaData.lua', { encoding: 'utf8'})
try {
  // Read in and parse the Lua table
  const obj = luaTableToJSObj(luaStr)

  // TODO: Modify the data here (however you want)

  // Write out the modified data as a Lua table
  fs.writeFileSync('./newLuaData.lua', JSObjToLuaTable(obj), { encoding: 'utf8' })
} catch(err) {
  console.error('Failed to parse lua table/JSON')
  console.error(err)
}

function luaTableToJSObj (luaString) {
  // Convert comments and remove newlines
  let JSONString = luaString.replace(/--(.*)/g, '//$1');
  JSONString = JSONString.replace(/^\s+?[\r\n]/gm, '')

  // Replace all '=' with ':'
  JSONString = JSONString.replace(/\=/g, ':');

  // Surround keys in quotes
  JSONString = JSONString.replace(/([\w]*)\s+\:/g, '"$1":');

  // Assume consecutive curly braces indicate arrays
  JSONString = JSONString.replace(/{{/g, '[{');
  JSONString = JSONString.replace(/}}/g, '}]');

  // Catch single-line arrays (with no keys)
  JSONString = JSONString.replace(/{([-\.\s\d,]+)}/g, '[$1]');

  // Try to parse (might throw an error)
  const obj = JSONC.parse(JSONString)
  return obj
}

function JSObjToLuaTable (JSObj) {
  let luaString = JSONC.stringify(JSObj, null, 2)

  // Change multi-line arrays to be in-line
  luaString = luaString.replace(/:\s*\[.+?\]/gs, (match) => {
    const inLined = match.replace(/\r?\n|\r/g, ' ')
    return inLined.replace(/\s+/g, ' ')
  });

  // Remove quotes around keys
  luaString = luaString.replace(/\"(\w*)\"\s*:/g, '$1 :')

  // Replace colon with equals
  luaString = luaString.replace(/:/g, '=')

  // Convert array square-braces to curly-braces
  luaString = luaString.replace(/\[/g, '{')
  luaString = luaString.replace(/\]/g, '}')

  // Convert '//' comments to '--' comments
  luaString = luaString.replace(/\/\/(.*)/g, '--$1');

  // Return the encoded lua
  return luaString
}