text: function contem(arr, val) {
    return arr.indexOf(val) !== -1 ? true : false;
  }
  let a = []; //array vazio
  //a.indexOf(0);
  console.log(contem(a, 0));
  let ar = ["a", "b"]; //array 2 elems
  console.log(contem(ar, 48));
  