如何仅在给定类名的情况下在运行时动态创建新的 Javascript 对象？

发布于 2024-12-25 10:05:23 字数 547 浏览 0 评论 0原文

假设有一些小部件：

function Widget1(initData) {
        ....
} 
Widget1.prototype.render = function() {
    ....
}


function Widget2(initData) {
    ....
}  
Widget2.prototype.render = function() {
    ....
}

我需要做的是：

$.subscribe('/launch', function(widgetName, initData) {
    // create a new object of the widget and then call the render method
});

我不想编写多个 if-else 块，因为小部件的数量可能会变得非常大。一种选择是使用 eval()，但我相信可能有更好的技术。我正在使用 JQuery 框架，因此不想包含任何其他可能具有支持此功能的特定功能的框架。纯 Javascript 解决方案将受到赞赏。

原文

Let us say there are some widgets:

function Widget1(initData) {
        ....
} 
Widget1.prototype.render = function() {
    ....
}


function Widget2(initData) {
    ....
}  
Widget2.prototype.render = function() {
    ....
}

What I need to do is the following:

$.subscribe('/launch', function(widgetName, initData) {
    // create a new object of the widget and then call the render method
});

I dont want to write multiple if-else blocks as the number of widgets may become very large. One option is to use eval(), but I believe that there may be better techniques. I am using JQuery framework, so don't want to include any other frameworks that may have a specific feature to support this. A pure Javascript solution will be appreciated.

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清醇 2025-01-01 10:05:23

是的，有办法。当您创建函数时，它会被创建为该上下文中 this 对象的属性。因此，如果您在全局范围内声明这些 Widget 函数，它们就会成为 window 对象的属性。您可能知道，您可以通过 object.property 或 object['property'] 来访问属性。因此，如果它们是全球性的，您可以执行以下操作：

$.subscribe('/launch', function(widgetName, initData) {
    var widget = new window[widgetName](initData);
});

编辑：正如 TJ Crowder 所说，我大错特错了。我所说的关于作为 this 的属性创建的函数适用于您位于全局范围内的情况（我想说“仅当您位于全局范围内时”，但因为我'我不是 100% 确定我会保持原样）。

Yep, there is a way. When you create a function, it's created as a property of the this object in that context. So if you declare those Widget functions in the global scope, they become properties of the window object. As you probably know, you can access a property both as object.property or object['property']. So, if they are global, you can do something like:

$.subscribe('/launch', function(widgetName, initData) {
    var widget = new window[widgetName](initData);
});

EDIT: As T.J. Crowder said, I was horribly wrong. What I said about the function being created as a property of this applies when you're on the global scope (I want to say "only when you're on the global scope", but since I'm not 100% sure I'm gonna leave it as that).

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倒数 2025-01-01 10:05:23

正如 Esalijia 的评论所说：

$.subscribe('/launch', function(widgetName, initData) {
    // create a new object of the widget and then call the render method
    widget = new window[widgetName]();
});

或者您可以使用 .bind() 来绑定定义 Widget* 的范围，并让它们可用于$.subscribe 方法。

As the comment from Esalijia said:

$.subscribe('/launch', function(widgetName, initData) {
    // create a new object of the widget and then call the render method
    widget = new window[widgetName]();
});

Or you can bind the scope of where Widget* is defined using .bind() and have them available to the $.subscribe method.

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