javascript javascript调用window对象上的函数
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javascript calling a function on window object
提问by timpone
I have the following code and am wondering how to make the last line work. I addopted a set of api's that current use _view appended as it's namespacing convention and would rather use something like arc.view.$function_name. thx
我有以下代码，想知道如何使最后一行工作。我添加了一组当前使用 _view 附加的 api，因为它是命名空间约定，并且宁愿使用诸如 arc.view.$function_name 之类的东西。谢谢
var arc={};
arc.view={
say_hello: function(){
alert("I want to say hello");
}
}
function say_goodbye(){
alert("goodbye to you");
}
arc.view.say_hello(); // works
window['say_goodbye'](); // works
// possible to make this work?
window['arc.view.say_hello']();
回答by zetlen
window['arc']['view']['say_hello']();
or
或者
window.arc.view.say_hello()
or
或者
window['arc'].view['say_hello']()
Either the dot syntax or the bracket syntax will work. Dot syntax is really just syntactic sugar for a bracket-based property lookup, so all of the above code snippets are identical. Use bracket syntax when the property name itself is a dynamic value, or when using the property name in dot syntax would cause a syntax error. E.g.:
点语法或括号语法都可以使用。点语法实际上只是基于括号的属性查找的语法糖，因此上述所有代码片段都是相同的。当属性名称本身是动态值时使用括号语法，或者在点语法中使用属性名称会导致语法错误。例如：
var dynamicMethodName = someObject.getMethodName();
someOtherObject[dynamicMethodName]();
or
或者
someOtherObject["a key string with spaces and {special characters}"]();
回答by ZER0
Using the square bracket notation you're actually asking to execute a function in window called arc.view.say_hello, and not a function in the object view(that is a property of the object arc). To be more explicit:
使用方括号表示法实际上是要求在调用的窗口中执行函数arc.view.say_hello，而不是对象中的函数view（即对象的属性arc）。更明确地说：
window["arc.view.say_hello"] = function () { alert("hi") };
window["arc.view.say_hello"](); // "hi"
If you want to call a function in the way you described, you have to "resolve" the objects chain. You can create an utility function for that. Something like:
如果你想以你描述的方式调用一个函数，你必须“解析”对象链。您可以为此创建一个实用程序函数。就像是：
var arc={};
arc.view={
say_hello: function(){
alert("I want to say hello");
}
}
function say_goodbye(){
alert("goodbye to you");
}
function call(id) {
var objects = id.split(".");
var obj = this;
for (var i = 0, len = objects.length; i < len && obj; i++)
obj = obj[objects[i]];
if (typeof obj === "function")
obj();
}
call("say_goodbye");
call("arc.view.say_hello");
You could also extend the utility function to use arguments(or you could just return the reference to the function).
您还可以扩展要使用的实用程序函数arguments（或者您可以只返回对该函数的引用）。
