benalu

#Benalu

A dynamic proxy for javascript. Provide a light weight proxy class generator with multiple interception.

###About The purpose of Benalu is provide a simple way to do a simple AOP in javascript. Benalu also useful for IOC container library that hasn't support for interception

###Features

• Can proxy a Function prototype or an object.

• Can proxy method & property

• Can add multiple interceptions

###Installation

npm install benalu

###How To Use It Using benalu is very simple. You start building your proxy by using Benalu builder

var Benalu = require('benalu');

//declare the class
function MyObject(){}
MyObject.prototype.getNumber = function(){
    return 700;
}

//create instance
var myObject = new MyObject();
     
//make a proxy   
var proxy = Benalu.fromInstance(myObject)
    .addInterception(function(i) {
        //filter the invocation
        if(i.methodName == "getNumber"){
            //call the real method
            i.proceed();
            //override the return value
            i.returnValue = 300;
        }
    })
    .build();
    
var numResult = proxy.getNumber();
//numResult become 300 vs 700

###Interception & Invocation Interception in Benalu simply a callback function with single parameter of Invocation. Invocation consist of 3 important members:

• methodName name of current invoked method. Usefull when you only want to intercept specific method of the class

• parameters arguments passed to the invoked method. Usefull when you want to get information of the arguments passed to the method.

• proceed() method to proceed current invocation. This method will invoke the method of the real object.

• returnValue return value of the current invoked method. this member filled automatically after the proceed() method called. You can override the return value of current invocation by suplying a value to the returnValue member

###Multiple Interception Benalu also support multiple interception.

var Benalu = require('benalu');

function MyObject(){}
MyObject.prototype.getNumber = function(){
    console.log("The real method called");
    return 700;
}

var myObject = new MyObject();
     
var proxy = Benalu.fromInstance(myObject)
    .addInterception(function(i) {
        if(i.methodName == "getNumber"){
            console.log("First interceptor before proceed");
            i.proceed();
            console.log("First interceptor after proceed");
            i.returnValue = 300;
        }
    })
    .addInterception(function(i) {
        if(i.methodName == "getNumber"){
            console.log("Second interceptor before proceed");
            i.proceed();
            console.log("Second interceptor after proceed");
            i.returnValue = i.returnValue + 300;
        }
    })
    .build();
    
var numResult = proxy.getNumber();
//numResult = 600

Above code will write log in the console like below:

Second interceptor before proceed
First interceptor before proceed
The real method called
First interceptor after proceed
Second interceptor after proceed