Find if a sequence represented by an array of items in some order is in a dataset that is presented as an array as well

hasSequence.js

function assertArray(v) {
  if (!Array.isArray(v)) {
    throw new TypeError(`Expected ${v} to be an array`)
  }
  return true
}

function hasSequence(data, seq) {
  assertArray(data)
  assertArray(seq)
  
  if (!data.length && !seq.length) {
    return true
  }
  
  let i = 0
  for (d of data) {
    const s = seq[i]

    if (d === s) {
      i += 1
    }

    if (i === seq.length) {
      return true
    }
  }

  return false
}

// examples:
// hasSequence(['a','b', 1, 'c', 2, 'd'], ['b', 2]) -> true
// hasSequence([],[]) -> true
// hasSequence(['a'], []) -> true
// hasSequence([], ['a']) -> false