whenOrNull<TResult extends Object?> method

TResult? whenOrNull<TResult extends Object?>(
  1. TResult? callback(
    1. List<UpdatedBook> updates,
    2. int? total,
    3. int page,
    4. int pageSize,
    )?
)

Invoke the original callback when supplied, otherwise return null.

Implementation

TResult? whenOrNull<TResult extends Object?>(
  TResult? Function(
    List<UpdatedBook> updates,
    int? total,
    int page,
    int pageSize,
  )?
  callback,
) => callback?.call(updates, total, page, pageSize);