pool/shard009/JavaScript/0056317_oo.js

// TODO:
// - test case
// - demo
void function (define) {
    define(function () {
        var Empty = function () { };
        var NAME_PROPERTY_NAME = '__eooName__';
        var OWNER_PROPERTY_NAME = '__eooOwner__';

        /**
         * 简单的 js oo 库
         *
         * 用法:
         *      @example
         *      // 来个简单的基类，最简单的是 var Super = Class();
         *      var Super = Class({
         *          superProp1: 'superProp1',
         *          superProp2: 'superProp2',
         *          method: function(){
         *              alert(this.superProp1);
         *          },
         *          superMethod2: function(){
         *              alert(this.superProp2);
         *          }
         *      })
         *
         *      // 来个派生类，继承 Super
         *      var Sub = Class(Super, {
         *          // constructor 会在实例化时调用
         *          constructor: function(prop){
         *             // $super 会自动调用父类的同名方法
         *             this.$super(arguments)
         *             this.subProp = prop
         *             alert("Sub init")
         *          },
         *          method: function(){
         *              this.$super(arguments);
         *              alert(this.subProp);
         *          }
         *      })
         *
         *      var Sub1 = Class(Sub, {
         *          constructor: function(prop1, prop2){
         *             this.$super(arguments)
         *             this.sub1Prop = prop2;
         *             alert("Sub1 init")
         *          },
         *          method: function(){
         *              this.$super(arguments)
         *              alert(this.sub1Prop)
         *          }
         *      })
         *
         *      var superIns = new Super();
         *      var sub = new Sub('Sub'); // alert: Sub init
         *      var sub1 = new Sub1('Sub', 'Sub1') // alert: Sub init, Sub1 init
         *      superIns.method() // alert: superProp1
         *      sub.method() // alert: superProp1, Sub
         *      sub1.method() // alert: superProp1, Sub, Sub1
         *      sub.superMethod() // alert: superProp2
         *      sub1.superMethod() // alert: superProp2
         *
         */

        /**
         * Class构造函数
         *
         * @class Class
         * @constructor
         * @param {Function | Object} [BaseClass] 基类
         * @param {Object} [overrides] 重写基类属性的对象
         * @return {Function}
         */
        function Class() {
            return Class.create.apply(Class, arguments);
        }

        /**
         * 创建基类的继承类
         *
         * 3种重载方式
         *
         * - '.create()'
         * - '.create(overrides)'
         * - '.create(BaseClass, overrides)'
         *
         * @static
         * @param {Function | Object} [BaseClass] 基类
         * @param {Object} [overrides] 重写基类属性的对象
         * @return {Function}
         */
        Class.create = function (BaseClass, overrides) {
            overrides = overrides || {};
            BaseClass = BaseClass || Class;
            if (typeof BaseClass === 'object') {
                overrides = BaseClass;
                BaseClass = Class;
            }

            var kclass = inherit(BaseClass);
            var proto = kclass.prototype;
            eachObject(
                overrides,
                function (value, key) {
                    if (typeof value === 'function') {
                        value[NAME_PROPERTY_NAME] = key;
                        value[OWNER_PROPERTY_NAME] = kclass;
                    }

                    proto[key] = value;
                }
            );

            kclass.toString = toString;

            return kclass;
        };

        /**
         *
         * @type {Function} creates a new object with the specified prototype object and properties.
         *  Just equals `Object.create` method.
         * @param proto {Object} The object which should be the prototype of the newly-created object.
         * @return {Object}
         */
        Class.static = typeof Object.create === 'function'
            ? Object.create
            : function (o) {
                if (arguments.length > 1) {
                    throw new Error('Second argument not supported');
                }
                if (!(o instanceof Object)) {
                    throw new TypeError('Argument must be an object');
                }
                Empty.prototype = o;
                return new Empty();
            };

        /**
         * 统一 toString 执行结果
         *
         * @static
         * @return {string}
         */
        Class.toString = function () {
            return 'function Class() { [native code] }';
        };

        Class.prototype = {
            constructor: function () {},
            $self: Class,
            $superClass: Object,
            $super: function (args) {
                var method = this.$super.caller;
                var name = method[NAME_PROPERTY_NAME];
                var superClass = method[OWNER_PROPERTY_NAME].$superClass;
                var superMethod = superClass.prototype[name];

                if (typeof superMethod !== 'function') {
                    throw new TypeError('Call the super class\'s ' + name + ', but it is not a function!');
                }

                return superMethod.apply(this, args);
            }
        };

        /**
         * 返回基类的一个继承对象
         *
         * @ignore
         * @param {Function} BaseClass 基类
         * @return {Function}
         */
        function inherit(BaseClass) {
            var kclass = function () {
                // 若未进行 constructor 的重写，则klass.prototype.constructor指向BaseClass.prototype.constructor
                return kclass.prototype.constructor.apply(this, arguments);
            };

            Empty.prototype = BaseClass.prototype;

            var proto = kclass.prototype = new Empty();
            proto.$self = kclass;
            if (!('$super' in proto)) {
                proto.$super = Class.prototype.$super;
            }

            kclass.$superClass = BaseClass;

            return kclass;
        }

        var hasEnumBug = !({ toString: 1 }.propertyIsEnumerable('toString'));
        var enumProperties = [
            'constructor',
            'hasOwnProperty',
            'isPrototypeOf',
            'propertyIsEnumerable',
            'toString',
            'toLocaleString',
            'valueOf'
        ];

        /**
         * hasOwnProperty函数的封装
         *
         * @ignore
         * @param {Object} obj 对象
         * @param {string} key 属性名
         * @return {boolean}
         */
        function hasOwnProperty(obj, key) {
            return Object.prototype.hasOwnProperty.call(obj, key);
        }

        /**
         * 遍历对象操作
         *
         * @ignore
         * @param {Object} obj 目标对象
         * @param {Function} fn 遍历操作
         */
        function eachObject(obj, fn) {
            for (var k in obj) {
                hasOwnProperty(obj, k) && fn(obj[k], k, obj);
            }
            //ie6-8 enum bug
            if (hasEnumBug) {
                for (var i = enumProperties.length - 1; i > -1; --i) {
                    var key = enumProperties[i];
                    hasOwnProperty(obj, key) && fn(obj[key], key, obj);
                }
            }
        }

        /**
         * toString method
         *
         * @ignore
         * @return {string}
         */
        function toString() {
            return this.prototype.constructor.toString();
        }

        return Class;
    });
}(typeof define === 'function' && define.amd ? define : function (factory) { module.exports = factory(require); });