JSFiddle - React, Tailwind, and code Playground

JavaScript

// This function is converted to string eventually and sent to worker
function WorkerFN() {
  console.log('WORKER: Worker ready for data.');
  console.info("indexedDB global variable: ",indexedDB);
  try{
   console.info("indexedDB in WorkerGlobalScope.prototype:");
   console.log(WorkerGlobalScope.prototype.indexedDB);
  }catch(e){console.error(e.message)};
  console.info("self.indexedDB: ",self.indexedDB);
  console.info("indexedDB in self =>","indexedDB" in self);
}
var url = "/echo/js/?js="+encodeURIComponent("("+WorkerFN.toString()+")()");

var worker = new Worker(url);