accurate-intervals

About

Provides functions for setting intervals that correct themselves in different ways.

Compatibility

Supports both CJS and ES6 import style.

// CommonJS-style
const {setAbsoluteInterval, setRelativeInterval, clearCustomInterval} = require("accurate-intervals");

// ES6 module-style
import {setAbsoluteInterval, setRelativeInterval, clearCustomInterval} from "accurate-intervals";

Install

npm i accurate-intervals

Features

Intervals that fire with respect to 0 milliseconds.

setAbsoluteInterval((delay)=>{
	console.log(`(${Date.now()}: Fired after ${delay} milliseconds.`);
}, 1000)

If Date.now() returns 123###, setting an absolute interval that fires every 1000 milliseconds should be expected to fire at 124000, 125000, 126000, 127000, etc...

The first time the interval fires, the delay can vary wildly.

• If you set it at 999999, it will want to fire after 1 millisecond.
• If you set it at 111111, it will want to fire after 889 milliseconds.

Intervals that fire with respect to when they were set.

setRelativeInterval((delay)=>{
	console.log(`(${Date.now()}: Fired after ${delay} milliseconds.`);
}, 1000)

If Date.now() returns 123###, setting a relative interval that fires every 1000 milliseconds should be expected to fire at 124###, 125###, 126###, 127###, etc...

Due to inherent unpredictability in the way intervals and timeouts work, the time between firing will vary, but it will always be between 0ms~1000ms (in this example). In my experience, you can expect it to vary by 0ms~25ms on average regardless of the actual interval assigned, with some spikes of 100ms~ or more uncommonly.

Cycle skipping.

Setting an interval below 30ms is inadvisable in pretty much all circumstances, as you may create a runaway condition where your interval will have to endlessly try to catch up. In order to avoid this scenario, these interval functions automatically skip cycles that are trying to catch up.

Canceling intervals.

const intervalID = setRelativeInterval((delay)=>{
	clearCustomInterval(intervalID);
	console.log("only fires once");
}, 1000);

clearCustomInterval clears intervals set by both setRelativeInterval and setAbsoluteInterval.