在coffeescript中测试类成员资格的最简单方法是什么？ [英] What is the easiest way to test for class membership in coffeescript?

问题描述

我正在寻找一个等价的Ruby的blah.is_a？（String） of Objective-C的 [@blahisKindOfClass ：[NSString class]]

I'm looking for an equivalent of Ruby's "blah".is_a?(String) of Objective-C's [@"blah" isKindOfClass:[NSString class]]

推荐答案

你想测试一个对象是否来自特殊类？然后，您需要 instanceof 关键字。 （它不是由CoffeeScript添加的东西，而是JavaScript的一部分。）CoffeeScript类被设置为，如果你写

Do you want to test whether an object is descended from a particular class? Then you want the instanceof keyword. (It's not something added by CoffeeScript; it's a part of JavaScript.) CoffeeScript classes are set up so that if you write

class A
class B extends A
class C extends B

true：

(new A) instanceof A
(new B) instanceof B and (new B) instanceof A
(new C) instanceof C and (new C) instanceof B and (new C) instanceof A

另外，任何对象将返回 true for instanceof Object 。

Also, any object will return true for instanceof Object.

如果要测试对象是其实例的特定类，请使用 .constructor 。例如，

If you want to test the specific class that an object is an instance of, use .constructor. For instance,

(new B).constructor is B

或如果您要使用字符串，

or if you'd like to use a string,

(new B).constructor.name is 'B'

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