Extending native Date using Prototype.js

gistfile1.js

/**
 * Some built-in browser types cannot be subclassed normally.
 * The following snippet demonstrates a perfect Date replacement.
 * 
 * Example use:
 *   CustomDate = Class.create(BaseDate, {
 *     // custom methods here...
 *   });
 */

'use strict';

self.BaseDate = Class.create({ /** @memberOf BaseDate */
    initialize: function(value) {
        if (arguments.length < 1) value = Date.now();
        else if (arguments.length > 1) value = Date.UTC.apply(null, arguments);
        this.date = new Date(value);
    },
    // Firefox-only feature
    __noSuchMethod__: function(name, args) {
        return this.date[name].apply(this.date, args);
    },
    // need to override inherited methods which are not changed by magic method
    toLocaleString: function() {
        return this.date.toLocaleString();
    },
    toSource: function() {
        return "(new BaseDate("+this.valueOf()+"))";
    },
    toString: function() {
        return this.date.toString();
    },
    valueOf: function() {
        return this.date.valueOf();
    }
});

// Test for Firefox-only feature
try {
    // Should do nothing if valid
    ({__noSuchMethod__:function(){}})._();
} catch(e) {
    // If no magic method then only choice is to list every possible method
    ["getDate","getDay","getFullYear","getHours","getMilliseconds","getMinutes","getMonth",
     "getSeconds","getTime","getTimezoneOffset","getUTCDate","getUTCDay","getUTCFullYear",
     "getUTCHours","getUTCMilliseconds","getUTCMinutes","getUTCMonth","getUTCSeconds","getYear",
     "setDate","setFullYear","setHours","setMilliseconds","setMinutes","setMonth","setSeconds",
     "setTime","setUTCDate","setUTCFullYear","setUTCHours","setUTCMilliseconds","setUTCMinutes",
     "setUTCMonth","setUTCSeconds","setYear","toDateString","toGMTString","toISOString","toJSON",
     "toLocaleDateString","toLocaleFormat","toLocaleTimeString","toTimeString","toUTCString"]
    .concat(Object.keys(Date.prototype)) // newly added methods
    .each(function(name) {
        BaseDate.prototype[name] = function() {
            return this.date[name].apply(this.date, arguments);
        };
    });
}