📦 mini-task-loop

📌 a simple javascript (node.js) library for managing scheduled async tasks for a loop.

Install

$ npm install mini-task-loop

Example

const TaskLoop = require('mini-task-loop');

// create our task loop with strict mode
let taskloop = new TaskLoop(true).runTaskLoop();

function test1()
{
	let counter = 0;

	// add first task run every 1000 milliseconds
	taskloop.addTask('first', 1000, (task_id) =>
	{
		counter ++;
		console.log(task_id + ' : ' + counter);

		// pause this task for 3 seconds when arriving 5 runs
		if (counter == 5)
		{
			taskloop.pauseTask(task_id);
			setTimeout(() => { taskloop.resumeTask(task_id); }, 3000);
			console.log(task_id + ' : waiting 3 seconds');
		}

		// remove this task after 10 runs
		if (counter >= 10)
		{
			taskloop.removeTask(task_id);
			console.log(task_id + ' : done');
		}

	}).executeOnce(); // make this task execute immediately after it's add
}

function test2()
{
	// using an object as the task id, run every 5 seconds.
	let obj = { id: 'second', foo: 'bar', counter: 0 };

	taskloop.addTask(obj, 5000, (task) =>
	{
		task.counter ++;
		console.log(task.id + ' : ' + task.counter);

		// stop the task loop after 4 runs
		if (task.counter >= 4)
		{
			// remove all task at this time
			taskloop.stopTaskLoop(true);
			console.log(task.id + ' : stop and exit');
		}
	});
}

test1();
test2();

// show all tasks we just added
console.log(taskloop.queryTask());

API

TaskLoop([strict_mode])

Constructor function of TaskLoop class.
An optional boolean to set strict mode of this object.
When strict mode is enabled, any operation of task will throw a runtime error if task id not matching in the loop.

runTaskLoop([loop_polling_interval])

Start running the task loop.

• @number loop_polling_interval : an integer to specify how many milliseconds between each process frame of task loop. default 100.
  • set this value based on average interval of tasks, smaller value means lower process latency of task scheduling.

stopTaskLoop([remove_all_task])

Stop running the task loop, existing tasks will be retained.

• @boolean remove_all_task : specify whether to remove all tasks in the task loop. default false.

addTask(id, interval, callback[, init_paused])

Add a new task to the task loop.

• @any id : an unique value or object used to identify the task.
• @number interval : an integer to specify how many milliseconds between each execution of the task.
• @function callback : called when task interval arrive in each times, id will passed to this function as param.
• @boolean init_paused : specify whether to pause this task when it added. default false.

addTask('foo', 1000, (task_id) =>
{
	// value of 'task_id' is referenced to 'foo'
});

removeTask([id])

Remove task from the task loop.

• @any id : if not specified, all tasks will be removed.

pauseTask([id, reset_counter])

Pause a running task.

• @any id : if not specified, all tasks will be paused.
• @boolean reset_counter : specify whether to reset task counter to zero. default false.

resumeTask([id, reset_counter])

Resume a paused task.

• @any id : if not specified, all paused tasks will be resume.
• @boolean reset_counter : specify whether to reset task counter to zero. default false.

queryTask([id])

Query task status. If task id not found, undefined will be returned.

• @any id : if not specified, a map iterator object that includes all task will be returned.

executeOnce([id, reset_counter, skip_paused])

Execute the task callback function.

• @any id : if not specified, all tasks callback will be executed.
• @boolean reset_counter : specify whether to reset task counter to zero. default false.
• @boolean skip_paused : specify whether to skip task execution if task is paused. default true.

Note

• The complete methods and description can be found in module.js
• More example see test.js and run test using npm test command.