Mutation 1 array

Tell us what’s happening:
it says type error arr[1] function.

Your code so far
function mutation(arr) {
var test= arr[1].toLowercase();
var target=arr[0].toLowercase();
for (var i=0; i<test.length; i++) {
if(target.indexOf(test[i])<0) return false;
}
return true;
}


function mutation(arr) {
var test= arr[1].toLowercase();
var target=arr[0].toLowercase();
for (var i=0; i<test.length; i++) {
  if(target.indexOf(test[i])<0) return false;
}
return true;
}




mutation(["hello", "hey"]);

Your browser information:

User Agent is: Mozilla/5.0 (Windows NT 6.1; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/87.0.4280.141 Safari/537.36.

Challenge: Mutations

Link to the challenge:

There’s a small typo.