“resend in Self”, on JavaScript ECMA-v5

Self中resend是调用“基类方法”的原语,它会把当前接收到的消息原样发送给其原型(parent*)。在ECMA-v5时代,我们终于可以做出这个伟大的东西了。

ECMA V5定义了一个期待已久的方法:Object.getPrototypeOf,它可以无视型别信息得到某对象的原型([[prototype]]),基于此,我们可以构造出一个resend:(请用Chrome 5、IE9预览第三版测试)

obj.resend = function() {
    var pof = Object.getPrototypeOf;
    var has = function() {......} // hasOwnProperty的封装
    var make = function(obj, old) {
        return function(name, args) {
            var step = pof(obj),
                r;
            while (step && !has(step, name)) step = pof(step);
            if (!step) throw new Error('Unable to resend: method missing');

            var foundMethod = step[name];
            var backup = arguments.callee;
            this.resend = make(this, backup);
            r = foundMethod.apply(this, Array.prototype.slice.call(arguments, 1));
            this.resend = old;
            return r
        }
    };

    return function(name, args__) {
        var rv;
        var old = this.resend;
        this.resend = make(this, old);
        rv = this.resend.apply(this, arguments);
        this.resend = original;
        return rv;
    }
}()
This entry was posted in Browser, 中文 and tagged , , , , , . Bookmark the permalink. Post a comment or leave a trackback: Trackback URL.

Post a Comment

Your email is never published nor shared. Required fields are marked *

*
*

You may use these HTML tags and attributes: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <strike> <strong>