Is array 1 a prefix of array 2? #javascript

isPrefixOf.js

// this is fully tail recursive
// also note that isPrefixOf([], []) is true
function isPrefixOf ([head1, ...tail1], [head2, ...tail2], prefixEquality = true) {
  if (!prefixEquality) return false;
  if (head1 === undefined) return true;
  if (head2 === undefined) return false;
  return isPrefixOf(tail1, tail2, head1 === head2);
}