compact<T> function

List<T> compact<T>(List<T> array)

Returns a new list with all null, empty, false, or NaN elements removed from the input list.

The compact function takes a list of elements of type T as input and returns a new list containing only the elements that are not null, not empty (for strings), not false (for booleans), not zero and not NaN (for numbers).

Example:

List<int> numbers = [1, 0, 3, null, 5, 6];
List<int> compactedNumbers = compact(numbers);
print(compactedNumbers); // Output: [1, 3, 5, 6]

Parameters:

• array: The list to compact.

Returns: A new list containing only the non-null, non-empty, non-false, and non-NaN elements from the input list.

Throws:

• Error: If the input list is null.

Note:

• For booleans, only true elements are included.
• For numbers, only non-zero and non-NaN elements are included.
• For strings, only non-empty elements are included.

Implementation

List<T> compact<T>(List<T> array) {
  return array.where((element) {
    if (element is bool) {
      return element;
    } else if (element is num) {
      return element != 0 && !element.isNaN;
    } else if (element == null) {
      return false;
    } else if (element is String) {
      return element.isNotEmpty;
    } else {
      return true;
    }
  }).toList();
}