transfer the title of all the worlds in the sentence to uppercase

titleCase.md

function titleCase(str) {
  var str1 = str.toLowerCase().replace(/\b(\w|')+\b/g, function(str){
  return str.substring(0,1).toUpperCase()+str.substring(1);
  }
  );
  return str1;
}
/*
  /\b(\w|')+\b/g
*/