js how to reduce size of string code example

Example 1: javascript set max length of string

String.prototype.trimEllip = function (length) {
  return this.length > length ? this.substring(0, length) + "..." : this;
}

Example 2: How to get length of string in javascript without using native length method

var str = userInput[0];
  var count = 0;
  while(str[count] !== undefined)
  {
      count += 1;
  }
  console.log(count)