// Return true if the string in the first element of the array contains 
// all of the letters of the string in the second element of the array.

function mutation(arr){
    const test = arr[1].toLowerCase();
    const target = arr[0].toLowerCase();

    for(let i = 0; i < test.length; i++){
        if(target.indexOf(test[i]) < 0) return false
    }

    return true;
}

console.log(mutation(["Alien", "line"]));