Take方法有什么用？颤动和飞镖

Question

采取-->它起到什么作用（flutter和Dart）

class Ticker {
  Stream<int> tick({int ticks}) => Stream.periodic(Duration(seconds: 1), (x) {
        return ticks - x - 1;
      }).take(ticks);
}

Answer 1

很简单，它只是将项目作为您从流中传递（ticks 参数）的计数。

// This stream is responsible to do a task for each second 
Stream.periodic(Duration(seconds: 1), (x) {
    return ticks - x - 1;
})

// With take, stream does it's job only `ticks` times
Stream.periodic(Duration(seconds: 1), (x) {
    return ticks - x - 1;
}).take(ticks);