AutoAnimate - Add motion to your apps with a single line of code

Created
May 27, 2022 1:17 AM
Type
image

A quick demo

AutoAnimate adds automatic animations to your JavaScript applications with a single line of code. Here's the same list component with and without AutoAnimate applied to the wrapping element:

That's a fairly notable improvement in UX for no additional developer effort! 🎉

Installation

Install using your package manager of choice to add @formkit/auto-animate to your project:

Aaaaand, you’re done! That was fast. 🐇

If you are using React, you can use the useAutoAnimate hook. If you are using Vue, you can use the v-auto-animate directive.

Usage

AutoAnimate is fundamentally a single function — autoAnimate — that accepts a parent element. Automatic animations will be applied to the parent element and its immediate children. Animations are specifically triggered when one of three events occurs:

  • A child is added in the DOM.
  • A child is removed in the DOM.
  • A child is moved in the DOM.

Let’s see what this looks like in practice. For now we'll use the autoAnimate function directly. React and Vue users — you’ll get some additional syntactic sugar later on — but for now let's learn the fundamentals:

import { useState, useRef, useEffect } from 'react' import autoAnimate from '@formkit/auto-animate' const Dropdown = () => { const [show, setShow] = useState(false) const parent = useRef(null) useEffect(() => { parent.current && autoAnimate(parent.current) }, [parent]) const reveal = () => setShow(!show) return <div ref={parent}> <strong className="dropdown-label" onClick={reveal}>Click me to open!</strong> { show && <p className="dropdown-content" >Lorum ipsum...</p> } </div> } export default Dropdown

Click me to open!

Too easy! A gentle, smooth shift without adding any transition classes or custom CSS. This is a notable upgrade for end users with minimal developer effort required. Checkout the examples to see other use cases.

Tips for success

  • It’s still ok to use other kinds of transitions. For example, if you are making stylistic changes with just CSS (such as a hover effect), then use standard CSS transitions for these kinds of styling tweaks.
  • Animations are only triggered when immediate children of the parent element (the one you passed to autoAnimate) are added, removed, or moved.
  • The parent element will automatically receive position: relative if it is statically positioned. Keep this in mind when writing your styles.
  • Sometimes flexbox layouts don’t resize their children immediately. A child with a flex-grow: 1 property waits for the surrounding content before snapping to its full width. AutoAnimate doesn’t work well in these cases, but if you give the element a more explicit width it should work like a charm.

Configuration

AutoAnimate is intended to be used with zero-configuration. We believe the default configuration falls in line with the project’s objective: AutoAnimate’s goal is to substantially improve an application’s user-experience without impacting the developer’s implementation time or performance budget. That said, some minor configuration options are available. AutoAnimate allows you to pass a second argument to autoAnimate with the following options:

autoAnimate(el, { // Animation duration in milliseconds (default: 250) duration: 250, // Easing for motion (default: 'ease-in-out') easing: 'ease-in-out' })

If your project’s specific requirements make it necessary to dramatically change the default animations, then you should check out the plugins documentation.

React hook

React users can use the hook useAutoAnimate by importing it from @formkit/auto-animate/react. This hook returns a ref to apply to the parent element:

import { useState } from 'react' import { useAutoAnimate } from '@formkit/auto-animate/react' const App = function () { const [items, setItems] = useState([0, 1, 2]) const [parent] = useAutoAnimate(/* optional config */) const add = () => setItems([...items, items.length]) return <> <ul ref={parent}> {items.map( item => <li key={item}>{ item }</li> )} </ul> <button onClick={add}>Add number</button></> } export default App

Vue directive

Vue users can globally register the v-auto-animate directive. This makes adding transitions and animations as easy as applying an attribute. Import the Vue plugin from @formkit/auto-animate/vue and register it with your Vue app:

Once you’ve registered the plugin, it can be applied anywhere in your application by adding the v-auto-animate directive to the parent element:

<script setup> import { ref } from 'vue' const items = ref(["😏","😐","😑","😒","😕", ... ]) function removeItem(toRemove) { items.value = items.value.filter((item) => item !== toRemove) } </script> <template> <h5>Click emojis to remove them.</h5> <ul v-auto-animate> <li v-for="item in items" :key="item" @click="removeItem(item)" > {{ item }} </li> </ul> </template>

Click emojis to remove them.

Vue users can pass options by directly setting the directive’s value <ul v-auto-animate="{ duration: 100 }">

Examples

Add and remove fruits from a list. Note that fruits are placed at random locations in the list to simulate injecting items rather than just pushing and unshifting.

Simulates showing a form to add an event to a list of event cards. Notice that it pushes it to the front of the list and all the cards animate to their destination, and the parent element (invisible) resizes smoothly to accommodate.

An important feature of AutoAnimate is that it operates on both the x and y axis. Items that are moved in the DOM from one location to another, or are wrapping at the end of a line will automatically be translated to their respective position.

We’ve all had to create accordions before. Pretty easy on the surface, but adding motion to the open/close sequence can be frustrating to say the least, and if you hack it together using max-height transitions, you are sure to lose your easing. No more!

  • We needed a way to animate DOM elements without adding to the virtual DOM in Vue and React. And it turned out our solution was gonna work great for lots of other use cases as well.

You don’t have to use FormKit to use AutoAnimate, but if you are a FormKit user, there are some neat things you can do. For example, you can use AutoAnimate to animate validation messages being added and removed from an input:

Plugins

While AutoAnimate is intended to be used with its zero-config defaults, some users may need to replace the default animation keyframes with custom ones. To do this, provide a function as the second argument of the autoAnimate function. This function will be called before every animation and must return a KeyframeEffect.

Here we will create a new set of keyframes for the add, remove and remain actions that overshoot their destinations to create a "bouncy" animation effect.

import autoAnimate, { getTransitionSizes } from '@formkit/auto-animate' autoAnimate(parentElement, (el, action, oldCoords, newCoords) => { let keyframes // supply a different set of keyframes for each action if (action === 'add') { keyframes = [ { transform: 'scale(0)', opacity: 0 }, { transform: 'scale(1.15)', opacity: 1, offset: 0.75 }, { transform: 'scale(1)', opacity: 1 } ] } // keyframes can have as many "steps" as you prefer // and you can use the 'offset' key to tune the timing if (action === 'remove') { keyframes = [ { transform: 'scale(1)', opacity: 1 }, { transform: 'scale(1.15)', opacity: 1, offset: 0.33 }, { transform: 'scale(0.75)', opacity: 0.1, offset: 0.5 }, { transform: 'scale(0.5)', opacity: 0 } ] } if (action === 'remain') { // for items that remain, calculate the delta // from their old position to their new position const deltaX = oldCoords.left - newCoords.left const deltaY = oldCoords.top - newCoords.top // use the getTransitionSizes() helper function to // get the old and new widths of the elements const [widthFrom, widthTo, heightFrom, heightTo] = getTransitionSizes(el, oldCoords, newCoords) // set up our steps with our positioning keyframes const start = { transform: `translate(${deltaX}px, ${deltaY}px)` } const mid = { transform: `translate(${deltaX * -0.15}px, ${deltaY * -0.15}px)`, offset: 0.75 } const end = { transform: `translate(0, 0)` } // if the dimensions changed, animate them too. if (widthFrom !== widthTo) { start.width = `${widthFrom}px` mid.width = `${widthFrom >= widthTo ? widthTo / 1.05 : widthTo * 1.05}px` end.width = `${widthTo}px` } if (heightFrom !== heightTo) { start.height = `${heightFrom}px` mid.height = `${heightFrom >= heightTo ? heightTo / 1.05 : heightTo * 1.05}px` end.height = `${heightTo}px` } keyframes = [start, mid, end] } // return our KeyframeEffect() and pass // it the chosen keyframes. return new KeyframeEffect(el, keyframes, { duration: 600, easing: 'ease-out' }) }))

We can use our newly defined keyframes in any previous example to see the effect it has. Here's our previous list example with the "bouncy" keyframes applied to it:

List example with "bouncy" keyframes

Why not...?

There are loads of Animation libraries available for JavaScript and each has its place. AutoAnimate is not a traditional animation library — think of it more as "Prettier for motion" — it is an easy-to-implement standard you can quickly apply to any project.

AutoAnimate’s goal is to smooth out changes to the DOM that are otherwise confusing to end-users. For example, when a user sorts a list with no animations, it is difficult to visualize how the items in the list have actually changed — but with AutoAnimate the changes suddenly make intuitive sense. AutoAnimate was made to solve this category of problem via a drop-in solution with zero-config.

Support us

Is AutoAnimate saving you time? Please consider supporting our open-source efforts with a recurring or one-time donation! 🙏