.includes() method mutations

Tell us what’s happening:
I know there was a similar post regarding using .includes() on mutations, but I think my problem might be slightly different (or maybe I didn’t understand the hint). I also know there is a solution using .indexOf(), but I’m curious as to why this isn’t working.

I can’t figure out for the life of me, why my “if” statement would evaluate to “false” with these arguments. I did a console.log of arr1[i] in this instance and it returns “a” which is included in “Aliens”.

Basically, no matter what I enter for arguments, “arr0.includes(arr1[i])” always evaluates to “false”.

I think I’m fundamentally misunderstanding something, but I’ve been at this for hours, so time to ask for help!

Your code so far

function mutation(arr) {

// code to return lower case array//
var arr0 = arr.map(function (x) {
  return x.toLowerCase();

//pop to remove second element from first//
var arr1 = arr0.pop();

// for loop to iterate over second array and evaluate against first array//
for (var i = 0; i < arr1.length; i++) {
  // why does this evaluate to false? //
  if (arr0.includes(arr1[i]) == false) {
    return false;
    return true;

mutation(["Alien", "line"]);

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Challenge: Mutations

Link to the challenge:

OK, I was trying to see if that statement is false, and if so to return false. I guess I misunderstood the method! Thanks!

Thank you! That gives me something to try later tonight! Thanks so much for your help!