Repeaters

A utility to create tracked, recurring, timed routines which repeat forever (or until aborted).

Install

npm install repeaters

Example Usage

const {RepeaterCollection} = require('repeaters');

const repeaters = new RepeaterCollection();

const repeatingTask = repeaters.add(async ({signal, delta, abort, count}) => {
    console.log(`Task interation #${count}`);
    console.log(`Milliseconds since last run: ${delta}`);

    await someLengthyAsyncFunc();

    if (signal.aborted) return; // if aborted, return early

    await anotherLengthyAsyncFunc();

}, {
    delay: 1000, // start running tasks after 1 second
    interval: 30*1000, // run task every 30 seconds
});

repeatingTask.on('run', (params) => console.log('run', params));
repeatingTask.on('abort', () => console.log('aborting'));
repeatingTask.on('aborted', () => console.log('aborted'));
repeatingTask.on('error', (err) => console.log('error', err));

setTimeout(() => {
    // abort after 5 minutes
    repeatingTask.abort();
}, 5*60*1000);

API

new RepeaterCollection();

Creates an empty collection of Repeaters.

RepeaterCollection#add(callback, options);

Create & add a new tracked Repeater to the collection.

• callback: A function to be called at the specified interval. The callback will be called until the Repeater is abort()ed.
• options:
  • interval: Milliseconds between each run of the task (defaults to 0 - runs immediately after previous invocation is complete).
  • delay: Milliseconds before the first run of the task (defaults to 0).
  • context: The this context to bind to the callback.

Returns: Repeater

RepeaterCollection#abort();

Calls abort() on every Repeater in the collection, attempting to stop any running tasks.

Returns a Promise which resolves after all running tasks have ended and are no longer scheduled to run.

Repeater

Repeater#abort();

Stops the recurring task and attempts to signal to any running task that it should return early.

Returns a Promise which resolves after the current running task has ended or when no more tasks are scheduled to run.

Repeater#on(eventName, listener)

Repeater#once(eventName, listener)

Repeater#removeListener(eventName, listener)

(See https://nodejs.org/api/events.html)