Пример реализации примера Java Sandbox

Ответ 1

Я упростил пример Stoyan, пытаясь понять, что происходит дальше. Я также прокомментировал это более подробно.

/*First define the modules of the sandbox.  These will be defined 
as properties on the constructor function because this is a 
convenient place to keep them.*/

Sandbox.modules = {};

Sandbox.modules.returnNumbers = function(MYAPP) {
    MYAPP.return100 = function() {return 100;};
};

Sandbox.modules.returnLetters = function(MYAPP) {
    MYAPP.returnABC = function() {return "ABC";};
};


function Sandbox() {

    /* Because Sandbox is a constructor, an new object is automatically 
    created.  Because we're in the constructor, we refer to this new object 
    as 'this'. 

    A constructor would typically be used as part of an assignment, e.g. 
    myObject = new Sandbox().  

    However, it also legitimate javascript to use a constructor without 
    the assignment by just writing new Sandbox() with no assignment.  The 
    constructor does return an object, it just that it doesn't get 
    assigned to anything so  is discarded.

    We're going to add functionality (methods) to the 'this' object, but 
    rather than returning it, we will pass it to the callback function, so 
    the methods can be used immediately.
    */

    var args = Array.prototype.slice.call(arguments);  //Put the arguments 
    //of the call to the Sandbox constructor in an array called args.

    var callback = args.pop(); //The last argument is the callback
    var requiredmodules = args;  //The remaining arguments are the require
    // modules

    //For each of the modules in 'requiredmodules', add the module 
    //methods to 'this'
    for (i=0; i< requiredmodules.length; i++) {
        Sandbox.modules[requiredmodules[i]](this);
    }


    //'this' now has methods returnNumbers and returnLetters

    //Call the callback.  In the example below, 'this' will be called 
    //MYAPP, which within the callback will have all the methods from 
    //the required modules.

    callback(this);

}



//Finally here is an example of usage

new Sandbox('returnNumbers', 'returnLetters', function (MYAPP) {

    console.log(MYAPP.return100());
    console.log(MYAPP.returnABC());
});

Ответ 2

Стоян Стефанов упоминает в той же главе, что YUI версия 3 реализует шаблон Sandbox. Метод добавления YUI (API) регистрирует модули и метод использования (API) загружает указанные в экземпляре песочницы, В документации API есть ссылки на исходный файл js. Фактически весь код YUI examples использует этот шаблон для работы с библиотекой YUI. Определение модуля редко необходимо - у YUI есть много основных и есть страница для настраиваемых модулей, добавленных сообществом.

Ответ 3

Итак, я попробовал и придумал это решение: http://jsfiddle.net/FhHSv/2/

Но я действительно неуверенная погода, это то, что я должен делать. Особенно добавление "модулей" несколько сбивает с толку. Также ранее в книге он использует шаблон пространства имен для этой задачи, но не здесь. Зачем? Вы тоже не можете это сделать? Но мне не удалось совместить эти два шаблона.

Пример шаблона пространства имен, вдохновленный книгой: http://jsfiddle.net/uWXgj/

Ответ 4

Вот пример с подробными комментариями:

    (function(){ 

/* function constructor */
function Sandbox(){
    //Change arguments to array, as you know 'arguments' are not a true JS array
    //Array.prototype.slice will provide shallow copy of 'arguments'
    var args = Array.prototype.slice.call(arguments),
        //remove last element from array and return it to caller
        //our last argument is callback
        callback = args.pop(), 
        //We can pass modules as strings or as array
        //if first element is a string, take all arguemnts
        //otherwise take one element (array)
        modules = (args[0] && typeof args[0] === "string") ? args : args[0],
        modulesLength = modules.length,
        i;

    //handle calling function constructor without 'new' keyword
    if(!(this instanceof Sandbox)){
        //Invoke me again!
        return new Sandbox(modules, callback);
    }

    //we can add properties to 'this'
    this.someProp = "Initialized property";

    //Initialize all required modules
    for(i = 0; i < modulesLength ; i++){
        //pass reference to 'this' for each required module and invoke it
        //'this' is poiting to new object which was created 
        //after calling new Sandbox()
        Sandbox.modules[modules[i]](this);
    }

    //Invoke callback and pass 'this'
    //now 'this' cotains all methods and properties
    //attached in modules functions
    callback(this);
};

//We can optionally create Sandbox methods
Sandbox.prototype = {
    version: "1.0.1",
    createdAt: new Date()
};

/* function as a first class object - saving all modules*/
Sandbox.modules = {}; 

/*Create $http,$scope and $ajax modules */
/*We need box object to add new functionality*/
/*We are creating new methods by attatching them to box obect*/
/*box is a reference to 'this' called as initializator from function constructor*/
Sandbox.modules.$http = function(box){

    box.get = function(){
        console.log("$http.get");
    };

    box.post = function(){
        console.log("$http.post");
    };

    box.prop = "I'm $http property";
};

Sandbox.modules.$scope = function(box){

    box.inject = function(param1, param2){
        console.log("$scope.inject: " + param1 + " " + param2);
    };

    box.destroy = function(o){
        console.log("$scope.destroy: " + o + " has been destroyed!");
    };

};

Sandbox.modules.$ajax = function(box){ 
    box.call = function(){
        console.log("$ajax.call");
    };     
};

//Sandbox without calling 'new' was handled in function constructor
//We are requesting for 2 modules: $scope and $http
//callback function is our new playground
//box object has $scope and $http methods and properties inside, we are ready to go!
Sandbox(["$scope", '$http'], function(box){ 
    console.log(box); //contains methods from $scope and $http
    console.log(box.inject("John", "Doe"));
    console.log(box.post());

    //we can event nest our playgrounds
    Sandbox(["$ajax"], function(box){
        console.log(box); //contains only $ajax methods and properties
        console.log(box.call());

        //we can't invoke $scope or $http functions here
    });

    //we can't invoke $ajax functions here
});
})();

Ссылка на JSFiddle: http://jsfiddle.net/Lodse4hj/