Implementación de ejemplo de JavaScript Sandbox

Question

En la página 101 del gran libro de Stoyan Stefanov "JavaScript Patterns", explica el patrón de sandbox. Me gustó mucho su libro pero realmente extrañé algunos ejemplos de la vida real aquí y luego para comprender mejor de lo que él habla. Like the sandbox pattern!

Busco una vida real aplicación de trabajo, como un punto de partida pasta de copia &, sólo un ejemplo sencillo que trabajará para entenderlo completamente.

¿Hay alguno?

Answer 1

He simplificado el ejemplo de Stoyan en un intento de facilitar la comprensión de lo que está sucediendo. También lo comenté más a fondo.

/*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's 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's 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's 
    //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()); 
}); 

Answer 2

así que he intentado y se acercó con esta solución: http://jsfiddle.net/FhHSv/2/

pero estoy clima muy seguro que esto es lo que debería hacer. Especialmente agregar los "módulos" es algo confuso. También antes en el libro usa el patrón de espacio de nombres para esta tarea, pero no aquí. ¿Por qué? ¿No puedes hacerlo aquí también? Pero no pude combinar estos dos patrones.

ejemplo patrón de espacio de nombre inspirado en el libro: http://jsfiddle.net/uWXgj/

Answer 3

Stoyan Stefanov menciona en el mismo capítulo que YUI version 3 implements the Sandbox pattern. The YUI add method(API) registra módulos y the use method(API) carga los especificados en la instancia de la caja de arena. Hay enlaces al archivo js de origen en la documentación de la API. Prácticamente todos los códigos YUI examples usan este patrón para trabajar con la biblioteca YUI. Definitivamente, no es necesario definir un módulo: YUI tiene muchos núcleos y existe un page para módulos personalizados agregados por la comunidad.

Answer 4

Aquí es ejemplo con comentarios detallados:

(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 
}); 
})(); 

Enlace a jsFiddle: http://jsfiddle.net/Lodse4hj/