API Reference

This document provides a detailed reference for the public API of tween.js.

Main Exports

These functions are exported from the main package entry point.

update(time?: number, preserve?: boolean): void

Updates all tweens in the main group. time is the current time in milliseconds. If not provided, performance.now() is used. preserve is a deprecated parameter.

getAll(): Tween[]

Returns an array of all tweens in the main group.

removeAll(): void

Removes all tweens from the main group.

add(tween: Tween): void

Adds a tween to the main group.

remove(tween: Tween): void

Removes a tween from the main group.

Tween<T> Class

The core class for creating an animation.

constructor(object: T, group?: Group | true)

Creates a new tween. * object: The object whose properties you want to animate. * group: An optional Group instance to add this tween to. Passing true adds it to the default main group (deprecated).

.to(target: object, duration?: number): this

Defines the target state of the animation. * target: An object with the final properties and values. * duration: The duration of the animation in milliseconds (default: 1000).

.start(time?: number, overrideStartingValues?: boolean): this

Starts the tween. * time: The start time in milliseconds. Defaults to the current time. * overrideStartingValues: If true, the tween will start from the current values of the object, not from the values at creation time.

.startFromCurrentValues(time?: number): this

Alias for .start(time, true).

.stop(): this

Stops the tween. The onStop callback is fired.

.end(): this

Immediately stops the tween and sets the object's properties to their final values. The onComplete callback is fired.

.pause(time?: number): this

Pauses the tween. The animation can be resumed with .resume().

.resume(time?: number): this

Resumes a paused tween.

.stopChainedTweens(): this

Stops all tweens that were chained from this tween.

.chain(...tweens: Tween[]): this

Chains one or more tweens to start after this one completes.

.delay(amount: number): this

Sets a delay in milliseconds before the tween starts.

.repeat(times: number): this

Sets the number of times the tween should repeat after the first run. Use Infinity for endless repetition.

.repeatDelay(amount: number): this

Sets a delay in milliseconds between repetitions.

.yoyo(yoyo: boolean): this

If true, the tween will reverse direction on every repetition. Requires .repeat() to be set.

.easing(easingFunction: Function): this

Specifies the easing function to use. See the Easing object below.

.interpolation(interpolationFunction: Function): this

Specifies the interpolation algorithm for array-based animations. See the Interpolation object.

.onStart(callback: (object: T) => void): this

Sets a callback that fires once when the tween begins (after any delay).

.onEveryStart(callback: (object: T) => void): this

Sets a callback that fires every time the tween begins (including repeats).

.onUpdate(callback: (object: T, elapsed: number) => void): this

Sets a callback that fires on every animation frame.

.onRepeat(callback: (object: T) => void): this

Sets a callback that fires when a repetition starts.

.onComplete(callback: (object: T) => void): this

Sets a callback that fires when the tween completes normally.

.onStop(callback: (object: T) => void): this

Sets a callback that fires when the tween is explicitly stopped.

Group Class

A class for managing a collection of tweens.

constructor(...tweens: Tween[])

Creates a new group and optionally adds initial tweens.

.getAll(): Tween[]

Returns an array of all tweens in this group.

.removeAll(): void

Removes all tweens from this group.

.add(tween: Tween): void

Adds a tween to this group.

.remove(tween: Tween): void

Removes a tween from this group.

.update(time?: number): void

Updates all tweens within this group.

Easing Object

A collection of built-in easing functions.

  • Easing.Linear.None
  • Easing.Quadratic.In, Easing.Quadratic.Out, Easing.Quadratic.InOut
  • Easing.Cubic.In, Easing.Cubic.Out, Easing.Cubic.InOut
  • Easing.Quartic.In, Easing.Quartic.Out, Easing.Quartic.InOut
  • Easing.Quintic.In, Easing.Quintic.Out, Easing.Quintic.InOut
  • Easing.Sinusoidal.In, Easing.Sinusoidal.Out, Easing.Sinusoidal.InOut
  • Easing.Exponential.In, Easing.Exponential.Out, Easing.Exponential.InOut
  • Easing.Circular.In, Easing.Circular.Out, Easing.Circular.InOut
  • Easing.Elastic.In, Easing.Elastic.Out, Easing.Elastic.InOut
  • Easing.Back.In, Easing.Back.Out, Easing.Back.InOut
  • Easing.Bounce.In, Easing.Bounce.Out, Easing.Bounce.InOut

Interpolation Object

A collection of algorithms for array interpolation.

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