Find character Locations: first-char, last-char, any Index position , index Number in String

CharLocation

/*
 *Below Function can find character Locations:
 * firstCharacter, lastCharacter, at any Index position
 * index Numbers in String
 */
String.prototype.charLocation = function(pos) {
  
  if(pos === 'first' || pos === "f" || pos === "F") {
    return this.charAt(0);
  }
  else if(pos === "last" || pos === "l" || pos === "L") {
    return this.slice(-1);
  }
  else if(typeof(parseInt(pos)) === "number") {
    return this.charAt(pos);
  }
  
};

var myName = "Manpreet";
//Returns character at last String of above variable
console.log(myName.charLocation("fl"));