js自定义继承方法

Class.js

var CTOR_NAME = 'initialize';

var extend = function(child, parent) {
    if (typeof parent === 'undefined') {
        parent = Object;
    }
    child.__super__ = parent;
    child.prototype.__proto__ = parent.prototype;

    var currnetClass = child;
    child.prototype.super = function(methodName) {
        // 把 arguments 转成数组
        var args = [].splice.call(arguments, 1);
        currnetClass = currnetClass.__super__;
        var result = currnetClass.prototype[methodName].apply(this, args);
        currnetClass = child;
        return result;
    }
};

var Class = function(properties, parent) {
    // 用 initialize 方法代替构造函数
    function ctor() {
        if (properties.hasOwnProperty(CTOR_NAME)) {
            properties[CTOR_NAME].apply(this, arguments);
        }
    }

    for (var key in properties) {
        if (!properties.hasOwnProperty(key)) {
            continue;
        }
        if (key === CTOR_NAME) {
            continue;
        }

        ctor.prototype[key] = properties[key];
    }

    // 继承
    extend(ctor, parent);

    return ctor;
};

module.exports = Class;

extends.js

var __hasProp = {}.hasOwnProperty;
__extends = function(child, parent) {
    for (var key in parent) {
        if (__hasProp.call(parent, key)) child[key] = parent[key];
    }

    function ctor() {
        // why set the prototype's constructor to child?
        this.constructor = child;
    }
    ctor.prototype = parent.prototype;
    child.prototype = new ctor;
    child.__super__ = parent.prototype;
    return child;
};


// test code
var parent = { arr: [1,2,3,4,5], hello: 'haha', world: 'hehe', myobj: {name: 'chrome', age: 22}};
var child = { a: '1', b: '2'};

var res = __extends(child, parent);
console.log(res);