Manage long-running tasks without losing interactivity
npm install chunked-queueManage long-running tasks without losing interactivity
One solution for this is to break the long-running task into chunks. Then,
each chunk can be run in a [setTimeout][] callback. If a higher-priority task
comes up, it will be able to run in between the chunks.
chunked-queue manages the list of chunks for you. You can even give it
multiple lists of chunks, and set (and update) priorities for each list,
to make sure the most urgent task finishes first.
Instead of [setTimeout][], chunked-queue uses [zero-timeout][], to avoid the
[minimum delay][] between setTimeout callbacks.
[setTimeout]: https://developer.mozilla.org/en-US/docs/Web/API/WindowOrWorkerGlobalScope/setTimeout
[zero-timeout]: https://github.com/GlobeletJS/zero-timeout
[minimum delay]: https://html.spec.whatwg.org/multipage/timers-and-user-prompts.html#timers
javascript
import * as chunkedQueue from 'chunked-queue';
`To initialize a new queue, call the
method, with no parameters:
`javascript
const queue = chunkedQueue.init();
`API
The initialized queue object exposes four methods$3
javascript
const taskId = queue.enqueueTask(newTask);
`The supplied
object may have the following properties:
- newTask.chunks (REQUIRED): An array of zero-argument functions, in the
order in which they are to be called. NOTE: These are assumed to be
synchronous
- newTask.getPriority (OPTIONAL): A method that when called, returns a
priority number for this task. Lower priority numbers will be run first.
If not supplied, this task will be given a constant priority of 0.The return value is an integer ID, which can later be used to cancel the task.
$3
`javascript
queue.cancelTask(taskId);
`
Cancels the task represented by the supplied taskId.$3
javascript
queue.sortTasks();
`
Sorts the tasks in the queue, according to the values returned by the
method on each task.This lets you re-set the priorities of the tasks after they are queued.
Simply update the
.getPriority methods to return smaller values for the
tasks which have become more urgent.$3
`javascript
numTasks = queue.countTasks();
``