listEquals<T> function Null safety

bool listEquals<T>(
  1. List<T>? a,
  2. List<T>? b

Compares two lists for element-by-element equality.

Returns true if the lists are both null, or if they are both non-null, have the same length, and contain the same members in the same order. Returns false otherwise.

If the elements are maps, lists, sets, or other collections/composite objects, then the contents of those elements are not compared element by element unless their equality operators (Object.==) do so. For checking deep equality, consider using DeepCollectionEquality class.

See also:

  • setEquals, which does something similar for sets.
  • mapEquals, which does something similar for maps.


bool listEquals<T>(List<T>? a, List<T>? b) {
  if (a == null)
    return b == null;
  if (b == null || a.length != b.length)
    return false;
  if (identical(a, b))
    return true;
  for (int index = 0; index < a.length; index += 1) {
    if (a[index] != b[index])
      return false;
  return true;