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1.1.3 • Public • Published

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A super simple, fast and easy to use tweening engine which incorporates optimized Robert Penner's equations.

Tweeno was originally created by refactoring Tween.js

Why I refactored Tween.js


Tweeno is a simple tweening engine designed to be used in html5 game development.

Library objects

  • Queue manages an array of tween objects updating them every update loop.
  • Tween handles the change of a target object's numeric property values over a span of time.
  • Filter assists in tweening numeric values within strings. For example rgba(10,20,30,1).
  • Easing equations for easing
  • Interpolation equations for interpolation

Example Usage

    /** nodejs / browserify **/
    var Tween = require('tweeno').Tween,
        Queue = require('tweeno').Queue,
        Easing = require('tweeno').Easing;
    /** browser **/
    var Tween = Tweeno.Tween,
        Queue = Tweeno.Queue,
        Easing = Tweeno.Easing;
    // creating a div to tween
    var targetDiv = document.createElement('div'); = 'position: absolute; left: 50px; top: 300px; font-size: 50px';
    // target object with internal state to be tweened
    var target = {
        x: 0,
        y: 0,
        div: targetDiv,
        // updates the div object state every update loop
        update: function(){
            var innerHTML = '',
            innerHTML += 'x: ' + Math.round(this.x);
            this.div.innerHTML = innerHTML;
   = this.x + 'px';
    // tween settings
    var settings = {
        // set when starting tween
        from: {
            x: 50,
            y: 0
        // state to tween to
        to: {
            x: 400,
            y: 20
        // 2 seconds
        duration: 2000,
        // repeat 2 times
        repeat: 2,
        // do it smoothly
        easing: Easing.Elastic.InOut,
    var queue = new Queue(),
        tween = new Tween(target, settings);
    // add the tween to the queue
    // start the queue
    // update loop
    var animate = function() {
        // update the queued tweens
        // update the target object state
    // start the update loop


Note: Tweeno has no dependencies

Nodejs / Browserify

$ npm install tweeno --save

var Tweeno        = require('tweeno'),
    Queue         = Tweeno.Queue,
    Tween         = Tweeno.Tween,
    Filter        = Tweeno.Filter,
    Easing        = Tweeno.Easing,
    Interpolation = Tweeno.Interpolation;


var Queue         = Tweeno.Queue,
    Tween         = Tweeno.Tween,
    Filter        = Tweeno.Filter,
    Easing        = Tweeno.Easing,
    Interpolation = Tweeno.Interpolation;



Tween objects manage the state of a target object over a span of time.

Tween(target, settings)

  • target object to tween the state of.
// example
  var target = {
      x: 0,
      y: 0,
      width: 10,
      height: 10
  • settings (optional) contains tween settings.
    // example
  var settings = {
      from: {
          x: 10,
          y: 10
      to: {
          x: 100,
          y: 10
      delay: 10,
      duration: 500,
      repeatDelay: 15,
      repeat: 4,
      yoyo: true,
      easing: Tweeno.Easing.Elastic.InOut,
      interpolation: Tweeno.Interpolation.Linear,
      chained: [], // array of tweens to be started when this tween is completed
      onStart:        false, // or: function(target, tween, easedProgress){},
      onYoYo:         false, // or: function(target, tween, easedProgress){},
      onRepeat:       false, // or: function(target, tween, easedProgress){},
      onUpdate:       false, // or: function(target, tween, easedProgress){},
      onComplete:     false, // or: function(target, tween, easedProgress){},
      filters:        false, // or: function(target, tween, easedProgress){},
var tween = new Tweeno.Tween(target, settings);

Settings Param

Name Type Default Description
from Object {} Starting state applied to the target when the tween starts (when tween.start() is called)
to Object {} Ending target state to be tweened to
delay Number 0 Delay in milliseconds (when repeat is set, only the first cycle is affected)
duration Number 1000 Tween duration in milliseconds
repeatDelay Number 0 Delay in milliseconds (when repeat is set, every cycle after the first is affected)
repeat Number false Number of times to repeat the tween
yoyo Bool false Reverses the tween every other repeat cycle starting with the second cylce (requires repeat to be set)
easing Function Tweeno.Easing.None Easing function, available in Tweeno.Easing (see list below)
interpolation Function Tweeno.Interpolation.Linear Interpolation function, available in Tween.Interpolation. (see list below)
onStart Function false Callback when started
onUpdate Function false Callback when updated
onRepeat Function false Callback when repeated (end of tween)
onYoYo Function false Callback when tween reversed (end of tween, every other repeat cycle)
onComplete Function false Callback when completed
filters Object false list of Tweeno.Filter objects indexed by the target object property name they are applied to (see more about filters below)
chained Array false list of Tween objects to add to the Queue object containing this Tween, when this Tween is complete.

Callback Parameters

All callback functions are given the same paramaters. onStart, onUpdate, onRepeat, onYoYo, onComplete

Name Type Description
target Object The target object of the tween calling the function
tween Object The Tweeno.Tween object calling the function
easedProgress Number Number between 0 and 1 showing current progress of the tween (easing function is already applied)
progress Number Number between 0 and 1 showing current progress of the tween
var settings = {
    onUpdate: function(target, tween, easedProgress, progress){
        // onUpdate callback code

Tween Settings After Creation

Any of the properties on the settings object can also be assigned or accessed directly on the tween object. They can be safely modified at any time before start() is called.

var target = {
    x: 0
var settings = {
    to: {
        x: 10
    repeat: 5
var tween = new Tweeno.Tween(target, settings);
// set or access any settings properties directly on the tween object before start() is called
tween.duration = 500;
tween.repeat = false;
// start the tween


Sets the startTime and prepares the Tween to begin.

  • startTime (optional) a timestamp to be used as the Tween startTime.

Returns: Tween object instance.

var tween = new Tweeno.Tween(target, settings);

When Tween.start() is Called:

  • The tween startTime is set automatically if none was specified.
  • The from object properties are applied to the target.


Updates the state of the Tween's target. The currentTime is compared to the startTime to determine the progress of the Tween. Tween.update() should be called every requestAnimationFrame() update loop. It is typically called by the Queue object containing the Tween via queue.update().

  • currentTime (optional) a timestamp to be used as the tween start time.

Returns: true if the Tween has not completed, false if it has.

var tween = new Tweeno.Tween(target, settings);
When Tween.update() is Called:
  • The onStart callback is called ( if not already called ).
  • The onUpdate callback is called.
  • The onRepeat callback is called ( if the end of the tween has been reached and the tween is set to repeat ).
  • The onYoYo callback is called ( if the end of the tween has been reached and the tween is set to repeat and yoyo).
  • The onComplete callback is called ( if the end of the tween has been reached ).


Returns: The total duration of the tween [ ( delay + duration) * repeat ]

    var tween = new Tweeno.Tween(target, settings);
    var duration = tween.getDuration();


A Queue object manages an array of Tweens. The Queue calls the tween.update() method of the tweens it contains every requestAnimationFrame() loop. Completed tweens are automatically removed from the queue.


  • tweens (optional) array of tweens to add.
    var tweens = [] // optional
    var queue = new Tweeno.Queue(tweens);


Adds a tween object to the queue.

  • tween Tween to add

Returns: Queue object instance.

var queue = new Tweeno.Queue();
var tween = new Tweeno.Tween(target, settings);


Removes a tween object from the queue.

  • tween Tween to remove

Returns: Queue object instance.


Note: Setting tween.remove = true will remove the tween from any queue it is in during the next queue.update().


Calls tween.start() on all Tweens in the queue, passing the startTime to each tween.start(startTime) in the Queue.

  • startTime (optional) a timestamp to be used as the startTime for all Tweens in the Queue.

Returns: Queue object instance.

var queue = new Tweeno.Queue();
var tween = new Tweeno.Tween(target, settings);
When Queue.start() is Called:
  • The tween startTime is set automatically if none was specified.


Calls tween.update() on all Tweens in the queue, passing the currentTime to each tween.update(currentTime) in the Queue.

  • currentTime (optional) a timestamp to be used as the tween.update(currentTime).

Returns: true if the Queue has any Tweens or false.

var queue = new Tweeno.Queue();
var tween = new Tweeno.Tween(target, settings);
When Queue.update() is Called:
  • Tweens that are completed or have tween.remove = true are removed from the queue.


Filters allow Tween objects to tween the numeric values within a string.


  • settings (optional) contains filter settings.
var settings = {
      placeholder: '%',
      format: 'rgba(%,%,%,%)',
      placeholderTypes: ['int', 'int', 'int', 'float']
var filter = new Tweeno.Filter(settings);

Settings Param

An object containing the settings for the tween object

Name Type Default Description
placeholder String % Placeholder for numeric values within the string
format String rgba(%,%,%,%) Format of the string to be filtered with placeholders where numeric values are to be placed
placeholderTypes Array ['int', 'int', 'int', 'float'] Array of strings 'int' or 'float' specifying the data type of the placeholder values, applied to each placeholder value in order of array index. example: ['int', 'int', 'int', 'float'] is equivalent to rgba(1, 2, 3, 0.75)


var queue = new Queue(),
    filter = new Filter({
        placeholder: '%',
        format: 'rgba(%,%,%,%)',
        placeholderTypes: ['int', 'int', 'int', 'float']
    target = {
        color: 'rgba(255,0,0,0)'
    settings = {
        to: {
            color: 'rgba(200,100,150,1)'
        filters: {
            color: filter
        duration: 500
    tween = new Tween(target, settings);


Converts a string to an array of numeric values.

  • str string to convert.

Returns: array of numeric values.

    var settings = {
        placeholder: '%',
        format: 'rgba(%,%,%,%)'
    var filter = new Tweeeno.Filter(settings);
    var str = 'rgba(5,6,7,1)';
    var arr = filter.stringToArray(str); // [5, 6, 7, 1]


Converts an array of numeric values to a string matching the format of the filter.

  • arr array to convert.

Returns: formatted string.

    var settings = {
        placeholder: '%',
        format: 'rgba(%,%,%,%)'
    var filter = new Tweeeno.Filter(settings);
    var arr = [5, 6, 7, 1];
    var str = filter.arrayToString(arr); // 'rgba(5,6,7,1)'

Changed from Tween.js


  • Simplified and better performing api
  • Extendable Objects with prototype properties and methods
  • Separation of Tween and Queue objects
  • Portability of config data via settings object
  • Exposed property values
  • More consistent callbacks with more params passed
  • Flexibility when delaying and repeating
  • Documentation
  • Unit Tests

New Features

  • String value filtering ( rgba(1,2,3,1) ) with interpolation support
  • npm, commonJS, AMD module loading

Easing Function Reference

  • Tweeno.Easing.Linear.None

  • Tweeno.Easing.Quadratic.In

  • Tweeno.Easing.Quadratic.Out

  • Tweeno.Easing.Quadratic.InOut

  • Tweeno.Easing.Cubic.In

  • Tweeno.Easing.Cubic.Out

  • Tweeno.Easing.Cubic.InOut

  • Tweeno.Easing.Quartic.In

  • Tweeno.Easing.Quartic.Out

  • Tweeno.Easing.Quartic.InOut

  • Tweeno.Easing.Quintic.In

  • Tweeno.Easing.Quintic.Out

  • Tweeno.Easing.Quintic.InOut

  • Tweeno.Easing.Sinusoidal.In

  • Tweeno.Easing.Sinusoidal.Out

  • Tweeno.Easing.Sinusoidal.InOut

  • Tweeno.Easing.Exponential.In

  • Tweeno.Easing.Exponential.Out

  • Tweeno.Easing.Exponential.InOut

  • Tweeno.Easing.Circular.In

  • Tweeno.Easing.Circular.Out

  • Tweeno.Easing.Circular.InOut

  • Tweeno.Easing.Elastic.In

  • Tweeno.Easing.Elastic.Out

  • Tweeno.Easing.Elastic.InOut

  • Tweeno.Easing.Back.In

  • Tweeno.Easing.Back.Out

  • Tweeno.Easing.Back.InOut

  • Tweeno.Easing.Bounce.In

  • Tweeno.Easing.Bounce.Out

  • Tweeno.Easing.Bounce.InOut

Interpolation Function Reference

  • Tweeno.Interpolation.Linear
  • Tweeno.Interpolation.Bezier
  • Tweeno.Interpolation.CatmullRom


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