IT工程師數位筆記本

/*!
 * defc
 * author: fsjohnhuang
 * version: 0.1.0
 * blog: fsjohnhuang.cnblogs.com
 * description: define class with single inheritance, multiple mixins
 * sample:
 *   defc('omg.JS', {
 *     ctor: function(version){
 *         this.ver = verison    
 *     },
 *     author: 'Brendan Eich',
 *     getAuthor: function(){ return this.author }
 *   })
 *   var ES5 = defc('omg.ES5', 'omg.JS', {
 *        ctor: function(version){}
 *   })
 *   var mixins = [{isGreat: true, hasModule: function(){return true}}]
 *   var ES6 = defc('omg.ES6', ES5, mixins, {
 *        ctor: function(version){},
 *      getAuthor: function(){
 *            var author = zuper() // invoke method of super class which is the same signature
 *            return [author, 'JSers']
 *      }
 *   })
 *   var es6 = new ES6('2015')
 *   var es6_copy = new ES6('2015')
 *   assert.deepEquals(['Branden Eich', 'JSers'], es6.getAuthor())
 *   assert.equals(true, es6.isGreat)
 *   ES6._mixin({isGreat: false})
 *   assert.equals(false, es6_copy.isGreat)
 *   
 *   defc.mixin(es6, {isGreat: true})
 *   assert.equals(true, es6.isGreat)
 *   assert.equals(false, es6_copy.isGreat)
 */
;(function(factory){
        var require = function(module){ return require[module] }
        require.utils = {
            isArray: function(obj){
                return /Array/.test(Object.prototype.toString.call(obj))
            },
            isFn: function(obj){
                return typeof obj === 'function'
            },
            isObj: function(obj){
                return /Object/.test(Object.prototype.toString.call(obj))
            },
            isStr: function(obj){
                return '' + obj === obj
            },
            noop: function(){}
        }

        factory(require, this)
}(function(require, exports){
    var VERSION = '0.1.0'
    var utils = require('utils')

    var clazzes = {}

    /**
     * @method defc
     * @public 
     * @param {DOMString} clzName - the full qualified name of class, i.e. com.fsjohnhuang.Post
     * @param {Function|DOMString|Array.<Object>|Object} [zuper|mixins|members] - super class, mixin classes array or members of class
     * @param {Array.<Object>|Object} [mixins|members] - mixin classes array or members of class
     * @param {Object} [members] - members of class. ps: property "ctor" is the contructor of class
     * @returns {Object}
     */
    var defc = exports.defc = function(clzName, zuper, mixins, members){
        if (clazzes[clzName]) return clazzes[clzName].ctor
        var args = arguments, argCount = args.length

        members = utils.isObj(args[argCount-1]) && args[argCount-1] || {}
        mixins = utils.isArray(mixins) && mixins || utils.isArray(zuper) && zuper || []
        zuper = utils.isFn(zuper) && zuper || utils.isStr(zuper) && clazzes[zuper] && clazzes[zuper].ctor || 0 

        var clz = clazzes[clzName] = {}
        var ctor = clz.ctor = function(){
            // execute constructor of super class
            if (zuper) zuper.apply(this, arguments)
            // execute constructor
            members.ctor && members.ctor.apply(this, arguments)
            // contruct public fields
            for(var m in members) 
                if(utils.isFn(this[m] = members[m])) delete this[m]
        }
        ctor.toString = function(){ return (members.ctor || utils.noop).toString() }

        // extends super class
        if (zuper){
            var M = function(){}
            M.prototype = zuper.prototype
            ctor.prototype = new M()    
            ctor.prototype.contructor = members.ctor || utils.noop
        }

        // construct public methods 
        for(var m in members)
            if(m === 'ctor' || !utils.isFn(members[m])) continue
            else if(!(zuper.prototype || zuper.constructor.prototype)[m]) ctor.prototype[m] = members[m]
            else (function(m){
                // operate the memebers of child within the methods of super class
                var _super = function(self){ return function(){ return (zuper.prototype || zuper.constructor.prototype)[m].apply(self, arguments)} }
                var fnStr = members[m].toString()
                    , idx = fnStr.indexOf('{') + 1
                    , nFnStr = fnStr.substring(0, idx) + ';var zuper = _super(this);' + fnStr.substring(idx)
                
                eval('ctor.prototype[m] = ' + nFnStr)
            }(m))

        // do shallow mixins
        for(var mixin in mixins)
            for(var m in mixins[mixin]) ctor.prototype[m] = mixins[mixin][m]

        // additional methods
        ctor._mixin = function(/*...mixins*/){
            var mixins = arguments
            for(var mixin in mixins)
                for(var m in mixins[mixin]) this.prototype[m] = mixins[mixin][m]
        }

        return ctor
    }

    /**
     * @method defc.mixin
     * @public
     * @param {Any} obj - mixin target
     * @param {...Object} mixins - mixin source
     */
    defc.mixin = function(obj/*, ...mixins*/){
        var mixins = Array.prototype.slice.call(arguments, 1)
        for(var mixin in mixins)
            for(var m in mixins[mixin]) obj[m] = mixins[mixin][m]
    }
}))