Question

我有以下声明可以在Javascript中轻松创建类。该课程来自本文：http://ejohn.org/blog/simple-javascript-inheritance/

问题在于，对象的选项似乎通过对象共享，但我需要它们作为实例变量。代码有什么问题？

代码：

/* Simple JavaScript Inheritance
 * By John Resig http://ejohn.org/
 * MIT Licensed.
 */
// Inspired by base2 and Prototype
(function() {
    var initializing = false, fnTest = /xyz/.test(function() {
        xyz;
    }) ? /\b_super\b/ : /.*/;

    // The base Class implementation (does nothing)
    this.NClass = function() {
    };

    // Create a new Class that inherits from this class
    NClass.extend = function(prop) {
        var _super = this.prototype;

        // Instantiate a base class (but only create the instance,
        // don't run the init constructor)
        initializing = true;
        var prototype = new this();
        initializing = false;

        // Copy the properties over onto the new prototype
        for (var name in prop) {
            // Check if we're overwriting an existing function
            prototype[name] = typeof prop[name] == "function" &&
                    typeof _super[name] == "function" && fnTest.test(prop[name]) ?
                    (function(name, fn) {
                        return function() {
                            var tmp = this._super;

                            // Add a new ._super() method that is the same method
                            // but on the super-class
                            this._super = _super[name];

                            // The method only need to be bound temporarily, so we
                            // remove it when we're done executing
                            var ret = fn.apply(this, arguments);
                            this._super = tmp;

                            return ret;
                        };
                    })(name, prop[name]) :
                    prop[name];
        }

        // The dummy class constructor
        function NClass() {
            var $this = this;
            // All construction is actually done in the init method
            if (!initializing && this.init)
                this.init.apply(this, arguments);
        }

        // Populate our constructed prototype object
        NClass.prototype = prototype;

        // Enforce the constructor to be what we expect
        NClass.prototype.constructor = NClass;

        // And make this class extendable
        NClass.extend = arguments.callee;

        return NClass;
    };
})();

(function (scope, undefined) {
scope.ssTypeBase = NClass.extend({
        options: {
            test: 0
        },
    init: function(test){
         this.options.test = test;   
    }
});

    var a = new scope.ssTypeBase(1);
    var b = new scope.ssTypeBase(2);
    console.log(a.options.test,b.options.test);
})(window);

Answer 1

原型属性始终在对象之间共享。因此，在这种情况下，如果您希望options对象是实例变量，那么在构造函数中设置选项对象就像这样

(function (scope, undefined) {
    scope.ssTypeBase = NClass.extend({
        sharedOptionsObject: {
            test: 0
        },
        init: function(test){
            // create options object here, it will create seperate options object for each instance

            this.options = {
                test: 0
            }
            this.options.test = test;   
        }
     });
});

Javascript类属性表现为共享变量

1 个答案: