如何在node.js中获得实例名称

Question

I have build a class "Queue" in node.js. I need some queues, so i make instances like "orderQueue": var orderQueue = new queue(); .

When the last element in a queue was processed, the queue should emit a signal like "orderQueue-processed" process.emit(instance.name + "-processed"); , which should be handled by my main program process.on(myobject.name + "-processed", function(){ addmorework ();});

But up to now i have not found out how i can get the name of the instance . Answers in stackoverflow do something with the window object, but it's not a bowser, it's node.js.

May be the idea to use the name is not good. A recommendation what to use instead and is easy to handle would be also very welcome.

Answer 1

There are two possible approaches to this that don't involved the name of the queue.

1. have your queue object act as an EventEmitter , so your main program creates instances of the queue, and then registers an event listener on it:

    var orderQueue = new queue(); queue.on("processed", function() { // Do something when this specific queue has been emptied }); 

2. Or, pass the object object as the event data:

    process.emit("processed",instance); 

   so the event listener is given the queue that emitted the event.

Answer 2

You can just assign the queue a name when you create it and then the queue will store the name as an instance variable:

function queue(name) {
    this.name = name;
    // other constructor code
}

var orderQueue = new queue("orderQueue");.

Then, when the last element in the queue is processed by a method on the queue, you can just get the name from the instance data for the queue:

process.emit(this.name + "-processed");