intersectsWith method

bool intersectsWith(Iterable<T> other)

Returns true if this Iterable has any items in common with the other Iterable. This method is as performant as possible, but it will be faster if any of the Iterables is a Set or an ISet.

Implementation

bool intersectsWith(Iterable<T> other) {
  //
  // Note: We could convert them to Sets, and check if Set.intersect is empty.
  // But that's not performant.

  // If both are Set/ISet we'll iterate the smaller one, because that's faster.
  if ((this is Set || this is ISet) && (other is Set || other is ISet)) {
    if (length > other.length) {
      for (final T item in other) {
        if (contains(item)) return true;
      }
      return false;
    }
    //
    else {
      for (final T item in this) {
        if (other.contains(item)) return true;
      }
      return false;
    }
  }

  // ---

  Iterable<T> set;
  Iterable<T> iterable;

  // If none of them is a Set/ISet, convert one of them to a Set.
  if ((this is! Set<T> && this is! ISet<T>) && (other is! Set<T> && other is! ISet<T>)) {
    set = other.toSet();
    iterable = this;
  }
  //
  // If one of them is a Set/ISet, find it.
  else {
    if (this is Set<T> || this is ISet<T>) {
      set = this;
      iterable = other;
    } else {
      assert(other is Set<T> || other is ISet<T>);
      set = other;
      iterable = this;
    }
  }

  /// Iterate the Iterable, searching the Set.
  for (final T item in iterable) {
    if (set.contains(item)) return true;
  }
  return false;
}