text: function mutation(arr) {
    let flag = 0;
    let resultArr = arr[1]
      .toLowerCase()
      .split("")
      .filter((x) => (arr[0].toLowerCase().indexOf(x) < 0 ? false : true));
  
    return resultArr.length === arr[1].length;
  }
  
  console.log(mutation(["hello", "hey"]));
  