如何在Dart中执行运行时类型检查？ [英] How to perform runtime type checking in Dart?

问题描述

Dart规范指出：

经过修改的类型信息反映了运行时对象的类型，并且始终可以通过动态类型检查结构来查询（
类似instanceOf，casts，typecase等）。

Reified type information reflects the types of objects at runtime and may always be queried by dynamic typechecking constructs (the analogs of instanceOf, casts, typecase etc. in other languages).

听起来不错，但没有<$类似于c $ c> instanceof 的运算符。那么我们如何在Dart中执行运行时类型检查？

Sounds great, but there is no instanceof-like operator. So how do we perform runtime type-checking in Dart? Is it possible at all?

推荐答案

instanceof-operator称为 is 在Dart中。该规范对休闲读者并不十分友好，因此，目前最好的描述似乎是 http：// www。 dartlang.org/articles/optional-types/ 。

The instanceof-operator is called is in Dart. The spec isn't exactly friendly to a casual reader, so the best description right now seems to be http://www.dartlang.org/articles/optional-types/.

以下是示例：

class Foo { }

main() {
  var foo = new Foo();
  if (foo is Foo) {
    print("it's a foo!");
  }
}

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