我可以通过修改函数原型在对象构造期间执行操作吗?

无法修改函数原型以便截获对函数的调用。最接近的方法是添加一个可以调用的方法来代替构造函数。例如:

Function.prototype.create = function() {
    var obj = new this();  // instantiate the object
    this.apply(obj, arguments);  // call the constructor

    // do your stuff here (e.g. add properties or whatever it is you wanted to do)
    obj.foo = 'bar';

    return obj;
};

function SomeObject(name) {
    this.name = name;
}

var obj = SomeObject.create('Bob');
obj.foo; // => 'bar'

或者,您可以编写一个函数,调用它来构建一个构造函数:

Function.makeConstructor = function(fn) {
    return function proxyConstructor() {
        // check to see if they called the function with the "new" operator
        if(this instanceof proxyConstructor) {
            var obj = new fn();
            fn.apply(obj, arguments);

            // do your stuff here (e.g. add properties or whatever it is you wanted to do)
            obj.foo = 'bar';

            return obj;
        } else {
            return fn.apply(null, arguments);
        }
    };
};

var SomeObject = Function.makeConstructor(function(name) {
    this.name = name;
});

var obj = SomeObject.create('Bob');
obj.foo; // => 'bar'