maxBy<K extends Comparable> method

T? maxBy<K extends Comparable>(K selector(T element))

Returns the element that yields the highest value based on the given selector. If the iterable is empty or all elements are null, it returns null.

The selector function is used to extract a comparable key from each element. The element with the highest value based on the selector is returned.

Example:

Iterable<int?>? numbers = [3, 5, 7, 2, null, 4];
int? result = numbers.maxBy((num) => num!);  // 7

Example with a custom object:

class Product {
  final String name;
  final double price;
  Product(this.name, this.price);
}

Iterable<Product?>? products = [
  Product('Apple', 1.5),
  Product('Banana', 0.8),
  Product('Mango', 2.0),
  null
];
Product? result = products.maxBy((product) => product?.price ?? 0.0);
print(result?.name);  // Mango

Implementation

T? maxBy<K extends Comparable>(K Function(T element) selector) {
  if (isEmpty) return null;

  T? maxElement;
  K? maxKey;

  for (final element in whereType<T>()) {
    // Filters out nulls
    final key = selector(element);
    if (maxKey == null || key.compareTo(maxKey) > 0) {
      maxElement = element;
      maxKey = key;
    }
  }
  return maxElement;
}