如何检查是否有拉斐尔物体？ [英] How can I check if something is a Raphael object?
问题描述
给定一个JavaScript对象，如何检查它是否是Raphael对象（不是纸张，而是圆圈，路径等）？
Raphael.el 表示通用元素原型;我想我要测试
x .__ proto__ === Raphael.el
以交叉浏览器的方式，但我不完全确定。
稍微详细说明并添加一些更相关的信息（我花了一点时间才弄清楚接受的答案，我显然不是唯一一个看其他答案，而且，接受的答案只能起作用对于一个类型的Raphael对象：它解决了原始问题，这是一个更完整的资源。）
检测拉斐尔元素
使用 x.constructor.prototype == Raphael.el ，你是取 x ，该变量可能是Raphael 元素 （圈子，路径等 - 不 a Raphael set 或 paper object）并将构建它的函数的原型与Raphael的原型进行比较拉斐尔本身的元素（ Raphael是一个函数对象，el是它的一个定义属性。
这有效，但它也找不到基于不同原型的raphael对象到Raphael.el ，像套装和纸张对象：
检测Raphael套装
如果你想测试某些东西是拉斐尔集合，那么集合原型是在 Raphael.st 中，所以你可以测试变量是否是拉斐尔集合使用：
someSet.constructor.prototype == Raphael.st
检测Raphael纸张对象
至于嗅探Raphael 纸张对象的等价物，因为它们是使用 Raphael（）函数创建，您可以使用：
paper.constructor.prototype == Raphael.prototype
以上三者与......基本相同/ p>
someSet.constructor.prototype == paper.circle（）。construc tor.prototype
...或...
someSet.constructor.prototype == paper.set（）。constructor.prototype
...或...
someSet.constructor.prototype == Raphael（）。constructor.prototype
...但是没有实际运行这些函数，所以避免浪费处理（并避免Raphael（）抱怨它还没有传递ID）。
检测物体的子类型（例如矩形，圆...）
以上都不适用于Raphael元素的子类型 - 例如如果你将一个圆与 R.rect（）。constructor.prototype 进行比较，它会返回 true 。
这是因为圆圈和矩形都是使用 Raphael.el中定义的元素原型制作的/ code>。然而，对于这些，拉斐尔让它变得简单：
someRectangle.type ==rect
someCircle.type ==circle
...等等。
Given a JavaScript object, how can I check if it is a Raphael object (not the paper, but a circle, path, etc.)?
Raphael.el represents the generic element prototype; I think I want to test
x.__proto__ === Raphael.el
in a cross browser way, but I am not completely sure.
To elaborate a little and add some more relevant info (it took me a little while to figure out the accepted answer, and I'm clearly not alone looking at the other answers, also, the accepted answer only works for one type of Raphael object: it solves the original question, this is a more complete resource).
Detecting Raphael elements
Using x.constructor.prototype == Raphael.el, you're taking x, the variable that might be a Raphael element (circle, path etc - not a Raphael set or paper object) and comparing the prototype of the function that constructed it with the prototype for Raphael elements in Raphael itself (Raphael is a function object, el is a defined property of it).
This works, but it also won't find raphael objects based on different prototypes to Raphael.el, like sets and paper objects:
Detecting Raphael sets
If you wanted to test if something was a Raphael set, the set prototype is in Raphael.st so you could test if a variable is a Raphael set using:
someSet.constructor.prototype == Raphael.st
Detecting Raphael paper objects
As for the equivalent for sniffing Raphael paper objects, since they are created using Raphael() function, you can use:
paper.constructor.prototype == Raphael.prototype
The above three are basically the same as...
someSet.constructor.prototype == paper.circle().constructor.prototype
...or...
someSet.constructor.prototype == paper.set().constructor.prototype
...or...
someSet.constructor.prototype == Raphael().constructor.prototype
...but without actually running those functions, so avoiding wasted processing (and avoiding Raphael() complaining that it hasn't been passed an ID).
Detecting sub-types of object (e.g. rectangle, circle...)
None of the above works for subtypes of Raphael elements - e.g. if you compare a circle with R.rect().constructor.prototype, it returns true.
This is because both circles and rectangles are made using the element prototype defined in Raphael.el. For these, however, Raphael makes it easy:
someRectangle.type == "rect"
someCircle.type == "circle"
...etc..
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