--description--

Given an array, determine if it is flat.

• An array is flat if none of its elements are arrays.

--hints--

isFlat([1, 2, 3, 4]) should return true.

assert.isTrue(isFlat([1, 2, 3, 4]));

isFlat([1, [2, 3], 4]) should return false.

assert.isFalse(isFlat([1, [2, 3], 4]));

isFlat([1, 0, false, true, "a", "b"]) should return true.

assert.isTrue(isFlat([1, 0, false, true, "a", "b"]));

isFlat(["a", [0], "b", true]) should return false.

assert.isFalse(isFlat(["a", [0], "b", true]));

isFlat([1, [2, [3, [4, [5]]]], 6]) should return false.

assert.isFalse(isFlat([1, [2, [3, [4, [5]]]], 6]));

--seed--

--seed-contents--

function isFlat(arr) {

  return arr;
}

--solutions--

function isFlat(arr) {
  for (let el of arr) {
    if (Array.isArray(el)) return false;
  }
  return true;
}