Create a method isIsogram that takes one argument, a word to test if it's an isogram. This method should return a boolean indicating whether it is an isogram. If the argument supplied is an empty string, return False.

isogram.js

function isIsogram(word){
  if (word !== undefined){
  const wordArr = word;
  if(word === ""){
    return false;
  }
  for (let i = 0; i < wordArr.length; i++) {
    for (let j = 0; j < wordArr.length; j++) {
        if(i!=j){
          if (wordArr[i] == wordArr[j]) {
              return false
          }
        }
    }
  }
  }
  return true;
}