async-task-mgr

var asyncTaskInstance = new asyncTask();

function taskAction(callback){
setTimeout(function(){ //simulate an async task
var resultA = Math.floor(Math.random()*100),
resultB = Math.floor(Math.random()*100),
resultC = Math.floor(Math.random()*100);

callback(resultA, resultB, resultC);
},2000);
}

//add a new task named task_A
//when taskAction is done, its return value will be saved and apply to all the task with the same name
asyncTaskInstance.addTask("task_A",taskAction,function(resultA,resultB,resultC){
console.log("task A_1 result :" + resultA + " " + resultB + " " + resultC); //all result generated by taskAction will be passed here
});

//add a new task named task_A
/*
since a task with the same name has been added, this taskAction will not be executed.
the callback function will be put in a queue and will be called when previous callbacks are done.
*/
asyncTaskInstance.addTask("task_A",taskAction,function(resultA,resultB,resultC){
console.log("task A_2 result :" + resultA + " " + resultB + " " + resultC);
});

//add a new task named task_X
//a new task, have no relationship to the previous ones
asyncTaskInstance.addTask("task_X",taskAction,function(resultA,resultB,resultC){
console.log("task X_0 result :" + resultA + " " + resultB + " " + resultC);
});