在Dart中创建新的reduce函数以简化对fold的调用

extension IterableUtils<T> on Iterable<T> {
  R myReduce<R>(R Function(R previousValue, T element) combiner, [R initialValue]) {
    R value = initialValue;
    for (var element in this) {
      value = combiner(value, element);
    }
    return value;
  }
}

void main() {
  List<int> numbers = [1, 2, 3, 4, 5];

  // 使用myReduce函数计算累加和
  int sum = numbers.myReduce((int previousValue, int element) => previousValue + element);
  print('Sum: $sum'); // 输出: Sum: 15

  // 使用myReduce函数计算累乘积，初始值为1
  int product = numbers.myReduce((int previousValue, int element) => previousValue * element, 1);
  print('Product: $product'); // 输出: Product: 120
}