Singleton Maker

singletonmaker.js

function singletonMaker(key, klassname, namespace) { 
  if (!window[namespace]) {
    window[namespace] = {};
  }

  const keySymbol = Symbol.for(key);
  const globalSymbols = Object.getOwnPropertySymbols(namespace);
  const hasKey = (globalSymbols.indexOf(keySymbol) > -1);
  
  if (!hasKey) {
    window[namespace][key] = new klassname();
    Object.seal(window[namespace][key]);
    return window[namespace][key];
 }
}