如何使用属性方法克隆原型？ [英] How to clone a prototype with property methods?

问题描述

我正在使用Typed.React库，该库包括一种将一个原型定义扩展为另一个原型定义的方法：

I am using the Typed.React library which includes a method to extend one prototype definition with that of another:

function extractPrototype(clazz) {
    var proto = {};
    for (var key in clazz.prototype) {
        proto[key] = clazz.prototype[key];
    }
    return proto;
}

如果提供的类定义了属性方法，则此函数具有执行副作用get方法，例如

If the provided class defines property methods, this function has a side effect of executing the get method e.g.

var TestObject = (function () {
    function TestObject() {
        this.str = "test string";
    }
    Object.defineProperty(TestObject.prototype, "TestProperty", {
        get: function () {
            console.log("exec get");
            return this.str;
        },
        set: function (value) {
            console.log("exec set");
            this.str = value;
        },
        enumerable: true,
        configurable: true
    });
    return TestObject;
})();

var extracted = extractPrototype(TestObject);

当extactPrototype访问TestObject.prototype [ TestProperty]时，它将执行属性get方法并打印：

When extactPrototype accesses TestObject.prototype["TestProperty"], it will execute the property get method and print:

exec get

我如何在不执行属性方法的情况下复制原型？

How would I duplicate a prototype with property methods without executing them?

推荐答案

我认为您正在寻找新的ES6 Object。分配 函数。

I think you are looking for the new ES6 Object.assign function.

当然，您的问题有一个更简单的解决方法-只是不访问和设置属性，复制它们的属性属性描述符：

Of course there's a simpler fix to your problem - just don't access and set properties, copy their property descriptors:

function extractPrototype(clazz) {
    var proto = {};
    for (var key in clazz.prototype) {
        Object.defineProperty(proto, key, Object.getOwnPropertyDescriptor(clazz.prototype, key));
    }
    return proto;
}

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