real-scheduler

Executes your callback repeatedly. Unlike the built-in setInterval method, real-scheduler avoids the excessive accumulation of timing errors in the long-run by making delay adjustments after each callback call.

Installation

npm install real-scheduler

Usage

executes a callback every delay milliseconds:

    new RealScheduler(callback, delay);

complete example

var RealScheduler = require('real-scheduler');

// create a Scheduler and run it automatically
// sch is a Scheduler's instance passed to a callback function
var scheduler = new RealScheduler((sch) => {
        console.log(
            // a real, accumulated time since the scheduler's start
            sch.getTimeElapsed() +
            // how many times this callback was called since the scheduler's start
            ": Call count: " + sch.getNumberOfCalls()
        );
        if (sch.getNumberOfCalls() == 60) {
            sch.stop(); //stop the scheduler
        }
    },
    100); //repeat every 100 milliseconds

Options

You can pass an options object as the Scheduler constructor's 3rd parameter:

    // sch is a Scheduler's instance
    var myOnStopHandler = function(sch) {
        console.log("on stop called");
    }

    new RealScheduler(callback, delay, {waitForTheFirstCall: false,
    onStop: myOnStopHandler});

Following optional parameters are possible:

• waitForTheFirstCall {boolean} - If true, waits for delay milliseconds before the first callback execution. Defaults to true.
• onStop {function} - A callback, called after a scheduler's stop() method is called. A function (sch) => {} where sch is an enclosing RealScheduler instance. Defaults to null.
• onDeltaError {function} - A callback, called after a time difference greater than delay occured. A function (sch) => {} where sch is an enclosing RealScheduler instance. Defaults to null.