A simple tweening library powered by TypeScript made for game dev for those who like their code to be type-safe and explicit in what it does.

This library was written in TypeScript but will also work in projects written in JavaScript.

Add it to your project via:

npm i --save evidently-tweens

The full documentation can be found here.

An example of using tweens:

import {TweenParallel} from "./TweenParallel";
import {TweenAnimate} from "./TweenAnimate";
import {TweenSequence} from "./TweenSequence";
import {TweenCallback} from "./TweenCallback";
import {TweenSleep} from "./TweenSleep";

const tween = new TweenParallel(
	() => console.log("Finished!"),
	new TweenAnimate(500, 0, 100, i => console.log(i)),
	new TweenSequence(
		undefined,
		new TweenCallback(() => console.log("Started!")),
		new TweenSleep(130),
		new TweenCallback(() => console.log("Yawn :3"))
	)
);

while (!tween.isFinished) {
	tween.advance(50);
}

Which will produce the following output in the console:

10
Started!
20
30
Yawn :3
40
50
60
70
80
90
100
Finished!

• The tweens operate on a unit-less duration, so you're free to use actual time or frames.
• There is no global, automatic runner, you need to call advance() on a tween instance to run it for specific amount of time.
• Every tween accepts a callback that's called when it finishes.
• advance() method accepts the duration for which the tweens should run and returns the amount of time consumed by that tween. For example, given a sleep tween with duration=50, if you call advance(60) on it, it will return 10, because the 50 units of duration were used to run the tween.
• The implemented tweens are:
  • TweenSleep which does nothing for the requested amount of duration (useful in TweenSequence or with a finished callback)
  • TweenCallback which instantly calls a function (useful in TweenSequence) and takes 0 duration.
  • TweenAwait which every time it runs calls a function, and if the function returns true it finishes. Takes 0 duration when it passes or all the available duration when it doesn't.
  • TweenAnimate animates a number with optional easing from certain value to another.
  • TweenParallel runs multiple tweens at the same time. On each run, advance() will return the amount of duration consumed by the longest tween in it, or 0 if there were no tweens to run.
  • TweenSequence runs tweens one after another. Any duration left from the execution of one tween will immediately be used on the next one. Thus, a single sequence with five TweenCallbacks in it will run all of them in the sigle call to advance()

This project is licensed under the MIT License - see the LICENSE.md file for details

• NPM
• Travis-ci