answer1.md

function isSubset(array1, array2) {
  const filterdArray2Set = [...new Set(array2)]; // return uniq array

  let subset = false
  filterdArray2Set.forEach((item) => {
    subset = array1.includes(item)
    if (!subset) return;
  });
  
  return subset
}

isSubset([A,B,C,D,E], [A,E,D])

O (n)