JSFiddle - React, Tailwind, and code Playground

JavaScript

function log(x) { document.body.innerHTML += x+"<br/>" }

function binConcat(){
	var str = "", ssize = 0;
  for(var i=0; i<1000000; i++) {  str = str+"a";  ssize+=str.length;  }
  log("Total length of all created strings: "+ssize+" bytes");
}

var time = Date.now();
binConcat();
log("binConcat time: "+(Date.now()-time));