extension method in dart

readme.md

Create by https://gist.github.com/CaiJingLong/a299d15b92edc2d09a8a06cf6dd5a1b0

main.dart

typedef void ForEachHandle<T>(int index, T item);

extension _A<T> on List<T> {
  void forEachIndexed(void func(int index, T item)) {
    for (var i = 0; i < this.length; i++) {
      func(i, this[i]);
    }
  }

  void forEachIndexed2(void Function(int index, T item) func) {
    for (var i = 0; i < this.length; i++) {
      func(i, this[i]);
    }
  }

  void forEachIndexed3(ForEachHandle<T> func) {
    for (var i = 0; i < this.length; i++) {
      func(i, this[i]);
    }
  }
}

void main() {
  [1, 2, 3].forEachIndexed((i, item) {
    print("index:$i , value: $item");
  });

  [1, 2, 3].forEachIndexed2((i, item) {
    print("index:$i , value: $item");
  });

  [1, 2, 3].forEachIndexed3((i, item) {
    print("index:$i , value: $item");
  });
}