node-func-queue

A simple NodeJS function sequence & concurrent execute Queue.

Installation

$ npm install func-queue

Usage

var queue = require('func-queue');

console.log("Queue test:");
var q = queue.createQueue(function(err, code) {
  console.log("error: " + err + " code: " + code);
}, function() {
  console.log("finished");
});
q.add(function(arg1) {
  console.log("step1, arg1: " + arg1);
  q.deliver(2, 3);
});
q.add(function( arg1, arg2) {
  console.log("step2, arg1: " + arg1 + " arg2: " + arg2);
  q.deliver();
});
q.add(function() {
  console.log("step3");
  q.append(function() {
    console.log("step4");
    return q.error("last", 4);
    console.log("This is never printed.");
  });
  q.deliver();
});
q.execute(1);

console.log("ConcurrentQueue test:");
var qa = queue.createConcurrentQueue(function(results) {
  console.log("ConcurrentQueue results:");
  for(var i=0; i<results.length; i++) {
    var result = results[i];
    console.log("key: %s, error: %j, successed: %j", result.key, result.error, result.successed);
  }
});
var q1 = qa.createQueue("k1");
q1.add(function() {
  setTimeout(function() {
    console.log("k1, func1");
    q1.deliver("q1 successed", 999);
  }, 100);
});
var q2 = qa.createQueue("k2");
q2.add(function() {
  console.log("k2, func1");
  q2.deliver();
});
q2.add(function() {
  setTimeout(function() {
    console.log("k2, func2");
    q2.error("q2 error");
  }, 200);
});
qa.execute();

Output

Queue test:
step1, arg1: 1
step2, arg1: 2 arg2: 3
step3
step4
error: last code: 4
ConcurrentQueue test:
k2, func1
k1, func1
k2, func2
ConcurrentQueue results:
key: k1, error: null, successed: {"0":"q1 successed","1":999}
key: k2, error: {"0":"q2 error"}, successed: null

API

---

createQueue(callback_error, callback_succssed, [callback_thisArg])

Creates a new query Queue.

callback_error([...])

The callback function was called when the Queue's function call error().

callback_successed([...])

The callback function was called when the Queue executed completed. It's parameters come from the last function call deliver().

callback_thisArg

The value of this provided for the call to callback_error() and callback_successed().

Queue.add(callback)

Add a delegate function. This query will be queued for execution until execute() was called by the Queue. Calling add() on an already executing Queue has throws an Exception.

Queue.append(callback)

Append a delegate function when the Queue already executing.

callback([...])

The current Queue object is its value of this when it called.

error([...])

Call it when the delegate function catch a error.

escape([...])

Call it when the delegate function escape the Queue as completed.

deliver([...])

Deliver to the next delegate function in the Queue.

Queue.execute([...])

Executes all function that were queued using Queue.add as sequence. Calling execute() on an already executing Queue has throws an Exception.

---

createConcurrentQueue(callback_done, [callback_thisArg])

Creates a new query ConcurrentQueue.

callback_done(results)

The callback function was called when the ConcurrentQueue's all child Queue was completed.

ConcurrentQueue.createQueue([key])

Create and add a child Queue, return the new Queue's instance. Don't direct call the Queue's execute(), it automatic be called until execute() was called by the ConcurrentQueue. Calling createQueue() on an already executing ConcurrentQueue has throws an Exception.

ConcurrentQueue.execute()

Executes all child Queue that were created using ConcurrentQueue.createQueue as concurrented. Calling execute() on an already executing ConcurrentQueue has throws an Exception.