親子関係を維持したオブジェクト継承

gistfile1.js

Object.prototype.mix = function(o) {
    var child = this,
        parent = {},
        ppropList = [];
    
    var contains = function(ary, value) {
        for (var i in ary) {
            if (ary.hasOwnProperty(i) && ary[i] === value) {
                return true;
            }
        }
        return false;
    };
    // for IE
    if (!!document.attachEvent) {
        for (prop in o) if (!contains(ppropList, prop)) {
            child[prop] = o[prop];
        }
    }
    // for Modern Browsers
    else {
        // Objectの独自拡張メソッドは追加しない
        for (var pprop in Object.prototype) {
            ppropList.push(pprop);
        }
        
        for (var prop in o) if (!contains(ppropList, prop)) {
            parent[prop] = o[prop];
        }
        
        // __proto__の深さを探索する
        var depth = 0, _c = child;
        for (;;) {
            _c = _c.__proto__;
            if (_c !== null) {
                depth++;
            }
            else {
                break;
            }
        }
        
        // 一番上の親を辿り__proto__にオブジェクトを連結する    
        var plist = ["child"];
        for (var i = 1; i <= depth; i++) {
            plist[i] = "__proto__";
        };
        eval(plist.join(".") + " = parent");
    }

    return child;
};

Object.prototype.parent = function() {
    return !!document.attachEvent ? this : this.__proto__;
};

var Telephone = {
    getPhoneName: function() {
        return "kurodenwa";
    },
    getType: function() {
        return "old type";   
    }
};

var Feature = {
    getPhoneName: function() {
        return "garake-";
    }
};

var Iphone = {
    getPhoneName: function() {
        return "iphone";
    }
};

// 複数継承
var o1 = Iphone.mix(Feature).mix(Telephone);
console.log(o1);

// 子
console.log(o1.getPhoneName()); // iphone
console.log(o1.parent().getPhoneName()); //garake-
console.log(o1.parent().parent().getPhoneName()); // kurodenwa
console.log(o1.getType()); // old type