Animate Plus is a JavaScript animation library focusing on performance and authoring flexibility. It aims to deliver a steady 60 FPS and weighs less than 2 KB (minified and gzipped), making it particularly well-suited for mobile.
npm install animateplus or download animateplus.js and start animating things:
import animate from "/animateplus.js";
animate({
elements: "div",
duration: 2000,
delay: index => index * 100,
transform: ["scale(0)", "scale(1)"]
})
.then(options => animate({
...options,
transform: ["translate(0%)", "translate(500%)"]
}));| Default | Type |
|---|---|
null |
String | Element | NodeList | Array |
Determines the DOM elements to animate. You can either pass it a CSS selector or DOM elements.
animate({
elements: document.body.children,
transform: ["rotate(0turn)", "rotate(1turn)"]
});| Default | Type |
|---|---|
out-elastic |
String |
Determines the acceleration curve of your animation.
| constant | accelerate | decelerate | accelerate-decelerate |
|---|---|---|---|
| linear | in-cubic | out-cubic | in-out-cubic |
| in-quartic | out-quartic | in-out-quartic | |
| in-quintic | out-quintic | in-out-quintic | |
| in-exponential | out-exponential | in-out-exponential | |
| in-circular | out-circular | in-out-circular | |
| in-elastic | out-elastic | in-out-elastic |
The amplitude and period of elastic easings can be configured by providing space-separated values.
Amplitude defaults to 1, period to 0.4.
// Increase elasticity
animate({
elements: "span",
easing: "out-elastic 1.4 0.2",
transform: ["translate(0px)", "translate(500px)"]
});| Default | Type |
|---|---|
1000 |
Number | Function |
Determines the duration of your animation in milliseconds. By passing it a callback, you can define a different duration for each element. The callback takes the index of each element as its argument and returns a number.
// First element fades out in 1s, second element in 2s, etc.
animate({
elements: "span",
easing: "linear",
duration: index => (index + 1) * 1000,
opacity: [1, 0]
});| Default | Type |
|---|---|
0 |
Number | Function |
Determines the delay of your animation in milliseconds. By passing it a callback, you can define a different delay for each element. The callback takes the index of each element as its argument and returns a number.
// First element fades out after 1s, second element after 2s, etc.
animate({
elements: "span",
easing: "linear",
delay: index => (index + 1) * 1000,
opacity: [1, 0]
});| Default | Type |
|---|---|
false |
Boolean |
Determines if the animation should repeat.
| Default | Type |
|---|---|
normal |
String |
Determines the direction of the animation. reverse runs the animation backwards, alternate
switches direction after each iteration if the animation loops.
| Default | Type |
|---|---|
1 |
Number |
Determines the animation playback rate. Useful in the authoring process to speed up some parts of a long sequence (value above 1) or slow down a specific animation to observe it (value below 1).
| Default | Type |
|---|---|
false |
Boolean |
Forces hardware acceleration during an animation if set to true. Unless you experience performance
issues, it's recommended to leave it off as hardware acceleration comes with potentially harmful
side-effects.
| Default | Type |
|---|---|
null |
Function |
Defines a callback invoked on every frame of the animation. The callback takes as its argument the
animation progress (between 0 and 1) and can be used on its own without being tied to elements.
// Linearly outputs the percentage increase during 5s
animate({
duration: 5000,
easing: "linear",
change: progress =>
document.body.textContent = `${Math.round(progress * 100)}%`
});Animate Plus lets you animate HTML and SVG elements with any property that takes numeric values, including hexadecimal colors.
// Animate the radius and fill color of an SVG circle
animate({
elements: "circle",
r: [0, 50],
fill: ["#80f", "#fc0"]
});Each property you animate needs an array defining the start and end values. For convenience, you can omit everything but the numbers in the end values.
// Same as ["translate(0px)", "translate(100px)"]
animate({
elements: "span",
transform: ["translate(0px)", 100]
});These arrays can optionally be returned by a callback that takes the index of each element, just like with duration and delay.
// First element translates by 100px, second element by 200px, etc.
animate({
elements: "span",
transform: index => ["translate(0px)", (index + 1) * 100]
});animate() returns a promise which resolves once the animation finishes. The promise resolves to
the object initially passed to animate(), making animation chaining straightforward and
convenient. The Getting started section gives you a basic promise example.
Since Animate Plus relies on native promises, you can benefit from all the usual features promises
provide, such as Promise.all, Promise.race, and especially async/await which makes animation
timelines easy to set up.
const play = async () => {
const options = await animate({
elements: "span",
duration: 3000,
transform: ["translateY(-100vh)", 0]
});
await animate({
...options,
transform: ["rotate(0turn)", 1]
});
await animate({
...options,
duration: 800,
easing: "in-quintic",
transform: ["scale(1)", 0]
});
};
play();Stops the animations on the elements passed as the argument.
import {stop} from "/animateplus.js";
animate({
elements: "span",
easing: "linear",
duration: index => 8000 + index * 200,
loop: true,
transform: ["rotate(0deg)", 360]
});
document.addEventListener("click", ({target}) => stop(target));Sets a timer in milliseconds. It differentiates from setTimeout() by returning a promise and being
more accurate, consistent and battery-friendly. The delay option relies internally on
this method.
import {delay} from "/animateplus.js";
delay(500).then(time => console.log(`${time}ms elapsed`));Animate Plus is provided as a native ES2015 module, which means you may need to transpile it
depending on your browser support policy. The library works as is using <script type=module> in
the following browsers:
- Chrome 61
- Safari 11.1
- Firefox 57 with
dom.moduleScripts.enabled
Animations play a major role in the design of good user interfaces. They help connecting actions to consequences, make the flow of interactions manifest, and greatly improve the polish and perception of a product. However, animations can be damaging and detrimental to the user experience if they get in the way. Here are a few best practices to keep your animations effective and enjoyable:
- Speed: Keep your animations fast. A quick animation makes a software feel more productive and responsive. The optimal duration depends on the effect and animation curve, but in most cases you should likely stay under 500 milliseconds.
- Easing: The animation curve contributes greatly to a well-crafted animation. The ease-out options are usually a safe bet as animations kick off promptly, making them react to user interactions instantaneously.
- Performance: Having no animation is better than animations that stutter. When animating HTML
elements, aim for using exclusively
transformandopacityas these are the only properties browsers can animate cheaply. - Restraint: Tone down your animations and respect user preferences. Animations can rapidly feel
overwhelming and cause motion sickness, so it's important to keep them subtle and to attenuate
them even more for users who need reduced motion, for example by using
matchMedia("(prefers-reduced-motion)")in JavaScript.
- Stress test: 500 elements animated concurrently.
- Morphing: CSS polygon morphing using
clip-path. - Motion path: Animation along a custom path.
- Line drawing: SVG line drawing animation.
- Elasticity: SVG circles following your clicks.
- Anchors: Anchor scrolling animation using
change(). - Progress: Animation progress using
change(). - Text: Text splitting animation.