Scheduler

Scheduler class are used by SlimIO Addons to schedule the execution of registered callbacks.

⚠️ Scheduler class are not designed to be precision timer (they are not a replacement of Node.js timers!).

Requirements

• Node.js v12 or higher

Getting Started

This package is available in the Node Package Repository and can be easily installed with npm or yarn.

$ npm i @slimio/scheduler
# or
$ yarn add @slimio/scheduler

Usage example

Scheduler are often use with SlimIO Addon(s) and are not designed to be used out of the SlimIO agent.

import Addon from "@slimio/addon";
import Scheduler from "@slimio/scheduler";

// Create your Addon
const myAddon = new Addon("myAddon");

// Create a sayHello function (our callback).
async function sayHello() {
    console.log("hello world!");
}

async function midnightJob() {
    console.log("executing at midnight!");
}

// Register "sayHello" callback and ask to schedule it every second (so it will be executed every second by Addon).
myAddon.registerCallback(sayHello)
    .schedule(new Scheduler({ interval: 1 }));

// Register "midnightJob" callback and schedule it every 24 hours at midnight
myAddon.registerCallback(midnightJob)
    .schedule(new Scheduler({ interval: 86_400, startDate: Scheduler.dateAtHours(24) }));

export default myAddon;

API

constructor(options?: CallbackScheduler.ConstructorOptions)

Construct a new Scheduler.

const myScheduler = new Scheduler({
    interval: 1250,
    intervalUnitType: Scheduler.Types.Milliseconds
});

Available options are the following:

argument name	type	default value	description
interval	number	36000	Default timer interval (in second if defaultType is not set)
startDate	date	Date.now()	The start date of the timer, dont set the property if you want the timer to start immediately
executeOnStart	boolean	false	The timer will return true on the very first walk() if this option is true
intervalUnitType	AvailableTypes	Types.seconds	Set the type of the interval

Available types are:

interface AvailableTypes {
    Milliseconds: "millisecond",
    Seconds: "second"
}

dateAtHours(hours?: number, minutes?: number, seconds?: number): Date

Create a "Date" Object with some given hours, minutes and seconds. By default all of these are assigned to 0.

const Scheduler = require("@slimio/scheduler");

const myDate = Scheduler.dateAtHours(10, 1, 1);
console.log(myDate.toString()); // stdout myDate with 10 hours, 1 minutes, 1 seconds and 0 milliseconds

// Same as
const myJSDate = new Date();
myJSDate.setHours(10, 1, 1, 0);

reset(): void

Reset the Scheduler (it will reset inner timestamp). This method is automatically called by the walk() method.

walk(): boolean

Walk the Scheduler. It will return false if the time is not elapsed and true if the time has been elapsed. When true is returned, the timer is automatically resetted !

Workflow of walk() method

Available Types

Scheduler support both Seconds and Milliseconds types.

interface Types {
    Milliseconds: "millisecond",
    Seconds: "second"
}

It's recommanded to set the type at the initialization of the Scheduler. (Avoir updating the type on the fly).

const timer = new Scheduler({
    interval: 500, // Ms
    intervalUnitType: Scheduler.Types.Milliseconds
});

timer.type = Scheduler.Types.Seconds;

Dependencies

This project have no dependencies.

License

MIT