Create scheduling task managers to perform tasks with prerequisites and priorities

Usage no npm install needed!

<script type="module">
  import dutie from 'https://cdn.skypack.dev/dutie';



Task Scheduling for Node.js!


npm install dutie // Some day, but this doesn't actually work yet

Task Manager


ALL PARAMATERS MUST BE OBJECTS. IF IT IS A NUMBER, DO SOMETHING LIKE { num: 2 } TO CONTAIN 2. I apologize for the inconvenience. If you know of another way for Arrays to contain pointers for primitives, please notify me :)

var Dutie = require('dutie');



Array of tasks waiting to be called. This sorts itself by priority when choosing next task. Don't expect it to be sorted any other time.


Current Task object that is running.



Just calls Dutie.update() which will recognize it has no task and needs to get one. It's pretty much just for the looks.


Add the task to Dutie.tasks Will checkAll to see if there are any changes or if the current one needs to be cancelled.

This returns itself so you can do Manager.add(TaskA).add(TaskB).add(TaskC);


Will make sure that each task that Task depends or is depended on will get added. Each of those will make sure theirs will get added. See Example Shortcuts for examples.


Update the current task. This will run anything in it's update method. If the update method return true, is will finish the task and try and get the next one. If finishing, will pass false to the cancel paramater in the finish method.


Force-finishes the task but still calls the task's Finish method. Bypasses whatever decision update() would have made. It will then decide what task is next. Will pass "true" to the cancel paramater in the finish method.


Calls the Task.finish(true), then adds it back to the list. WARNING: This will leave currentTask as null unless you do something about it! You're probably not gonna use this one since we take care of priority canceling.


Murder the current task. Guillotine it and don't call its finish. Still replaces itself. I don't recommend killing your fellow tasks. Just use finish even if you don't have a finish method.


Calls Task.check() on every task. This COULD change the current task if a Task.check() passes true and has a higher priority than the current Task! Every task is checked when deciding the next Task, so don't worry about it if you don't have to.


var Task = Dutie.Task


An array of Tasks it depends on to finish. Tasks will be removed from the list if they have finished/failed/ended The Task cannot execute until this array is empty.


Will push TaskB to TaskA.depend


TaskB will depend on TaskA


Does the exact same as Dutie.add except it adds itself to the specified Manager


Will make sure that each task that Task depends or is depended on will get added. Each of those will make sure theirs will get added. It continues on. None will get added twice. See Example Shortcuts for examples.


Update method that you pass. Change if you must... or just write a better update method that you don't have to change. The update method gets called whenever you wants to. It allows you to complete your action or return true to end it.


Array of params to be called with each update. This is why you do Dutie.update() instead of Task.update(). Silly goose.


When a task finishes (if you weren't silly enough to use Dutie.endTask()) this method will be called. IMPORTANT: The "cancel" paramater comes before any of your custom paramaters. This means if you have: [a, b, c] in your finishParams, it will call Task.finish(cancel, a, b, c). Thank you for your time :)


Same as Task.updateParams but for finish. Remember that important note in Task.finish.


Method that is run to check if you can execute the task. This is if you want to depend on something that is not a task. If you want to be able to execute the task, return true.


Array of paramaters passed to Task.check.


Function that gets called immediately when the task begins. Return true to finish immediately (useful for "prerequisites")


Array of paramaters passed to Task.start.


Calls with finish except only if the task was cancelled.


Array of paramaters passed to Task.cancel.


Calls with finish except only if the task was succesful.


Array of paramaters passed to Task.cancel.

new Task(update, updateParam, options)

Congrats! You've created your new Task object! But what do you put in it?


This is your update method! Put in here what you'd like to do during your task. Once your task is complete, return true!


Your update is going to be called with these paramaters, just for you. Make them count! Just in case you're wondering: this is an array.


Explained in other places. Prioritises which task should be executed first.


Also explained it other places. How much priority it has while executing.


Alright, you've made it this far. What are the options?

  • priority: Default is 0. Think of this as "How important is it that the task starts?"
  • actPriority: Defaults to priority. Think of this as "How important is it that the task finishes (after starting)"
  • finish: Method that gets called when your task is finished with a bool if it canceled or not and finishParams
    • Ex: finish(cancel_bool, finishParam_0, finishParam_1)
  • finishParams: Array of paramaters passed to finish
  • check: See Task.check. This is a function
  • checkParams: Array of paramaters passed to check
  • start: See Task.start.
  • startParams: Array of paramaters passed to start
  • cancel: See Task.cancel
  • cancelParams: Array of paramaters passed to cancel
  • complete: See Task.complete
  • completeParams: Array of paramaters passed to complete


var CallTask = Dutie.CallTask

CallTasks are built for callbacks rather than updates. This means your call function is now the method you wish to pass the callback with. The callback is automatically put at the end of the paramaters or at Task.location as set when created in the options.

Your "start" method is called before the call function is request. Use this in to make sure you want to send the request!

new CallTask(call, callParams, options)

Very similar to new Task() except you are passing start and startParams now. Since the default Task.location is the end of startParam, you'll most likely have on less paramater on the end.


function add(a, b, callback) {
    callback(a + b);

Manager.add(new CallTask(add, [1, 3], { complete: console.log })); // Task's callback is automatically added to end
// Should output 4


CallTask includes all of the original options in Task plus:

  • location: Location of callback (will replace startParams position).
  • update: Update function as in Task. You probably won't need this since that would be two ways to end the Task.
  • updateParams: Array of paramaters passed to update

Example Task

There is an example task.js provided in addition to the following:

Let's say you have a Minecraft bot that needs to mine ore and then go home but then runs into a zombie!

var Dutie = require('dutie');
var Task = Dutie.Task;

var Manager = new Dutie();

var mine = new Task(mineOreFunction, [], { priority: 3, actPriority: 6, finish: function(bot) {
}, finishParam: [bot]}); // Mine ore task
var home = new Task(goHomeFunction, [true], { priority: 4, actPriority: 8}); // Go home task, passing "true" paramater as an example
home.dependOn(mine); // Bot cannot go home until it finishes mining (or mining fails / ends)


/////////////// / / /
/// Somewhere else
/////////////// / / /

var zombie = new Task(killZombieFunction, [], { priority: 20, actPriority: 20});
Manager.add(zombie); // Will now cancel the mine task, adding it back into the line, and make zombie the current (since it has a higher priority then mine's actPriority)

/////////////// / / /  /   /   /
/// Somewhere else... again...
/////////////// / / /  /   /   /

// Let's sleep when we get home
// We don't know if there's a home task or not though (or we don't remember which one)
// Instead, we give a "check" with makes it dependent on something other than a task.

var sleep = new Task(goToSleep, ['home'], { priority: 3, actPriority: 3, check: function(bot) {
    if (bot.position.atHome()) return true;
    return false;
}, checkParams: [bot]});

Manager.checkAll(); // This is automatically called at the end of a task, at a cancel, etc, but feel free to call it yourself if you need to
// Returns false because not at home.

// Even if it does return true, it needs to have a higher priority than actPriority to overtake
// Or it needs the highest priority in the list at the end of a task.

Example CallTask and RunTask

See the examples folder for some basic uses of these. Both can use most of the functionality as the task example.

Example Shortcuts

var m = some manager;
var task = some task;
var task_two = some other task;
var task_three = some last task;






task_two.dependOn(task); // Think of as "___ depends on ____"
// Same as
task.dependBy(task_two); // Think of as "___ depended on by ____"