Vue Animations
The built-in <Transition> component in Vue helps us to do animations when elements are added or removed with v-if, v-show or with dynamic components.
There is nothing wrong with using plain CSS transitions and animations in other cases.
A Short Introduction to CSS Transition and Animation
This part of the tutorial requires knowledge about basic CSS animations and transitions.
But before we use the Vue specific built-in <Transition> component to create animations, let's look at two examples of how plain CSS animations and transitions can be used with Vue.
Example
App.vue:
<template>
<h1>Basic CSS Transition</h1>
<button @click="this.doesRotate = true">Rotate</button>
<div :class="{ rotate: doesRotate }"></div>
</template>
<script>
export default {
data() {
return {
doesRotate: false
}
}
}
</script>
<style scoped>
.rotate {
rotate: 160deg;
transition: rotate 1s;
}
div {
border: solid black 2px;
background-color: lightcoral;
width: 60px;
height: 60px;
}
h1, button, div {
margin: 10px;
}
</style>
In the example above, we use v-bind to give the <div> tag a class so that it rotates. The reason that the rotation takes 1 second, is that it is defined with the CSS transition property.
In the example below, we see how we can move an object with the CSS animation property.
Example
App.vue:
<template>
<h1>Basic CSS Animation</h1>
<button @click="this.doesMove = true">Start</button>
<div :class="{ move: doesMove }"></div>
</template>
<script>
export default {
data() {
return {
doesMove: false
}
}
}
</script>
<style scoped>
.move {
animation: move .5s alternate 4 ease-in-out;
}
@keyframes move {
from {
translate: 0 0;
}
to {
translate: 70px 0;
}
}
div {
border: solid black 2px;
background-color: lightcoral;
border-radius: 50%;
width: 60px;
height: 60px;
}
h1, button, div {
margin: 10px;
}
</style>
The <Transition> Component
There is nothing wrong with using plain CSS transitions and animations like we did in the two examples above.
But luckily Vue provides us with the built-in <Transition> component in cases where we want to animate an element as it is removed from, or added to, our application with v-if or v-show, because that would be hard to do with plain CSS animation.
Let's first make an application where a button adds or removes a <p> tag:
Example
App.vue:
<template>
<h1>Add/Remove <p> Tag</h1>
<button @click="this.exists = !this.exists">{{btnText}}</button><br>
<p v-if="exists">Hello World!</p>
</template>
<script>
export default {
data() {
return {
exists: false
}
},
computed: {
btnText() {
if(this.exists) {
return 'Remove';
}
else {
return 'Add';
}
}
}
}
</script>
<style>
p {
background-color: lightgreen;
display: inline-block;
padding: 10px;
}
</style>
Now let's wrap the <Transition> component around the <p> tag, and see how we can animate the removal of the <p> tag.
When we use the <Transition> component, we automatically get six different CSS classes we can use to animate when elements are added or removed.
In the example below we will use the automatically available classes v-leave-from and v-leave-to to make a fade out animation when the <p> tag is removed:
Example
App.vue:
<template>
<h1>Add/Remove <p> Tag</h1>
<button @click="this.exists = !this.exists">{{btnText}}</button><br>
<Transition>
<p v-if="exists">Hello World!</p>
</Transition>
</template>
<script>
export default {
data() {
return {
exists: false
}
},
computed: {
btnText() {
if(this.exists) {
return 'Remove';
}
else {
return 'Add';
}
}
}
}
</script>
<style>
.v-leave-from {
opacity: 1;
}
.v-leave-to {
opacity: 0;
}
p {
background-color: lightgreen;
display: inline-block;
padding: 10px;
transition: opacity 0.5s;
}
</style>
The Six <Transition> Classes
There are six classes automatically available to us when we use the <Transition> component.
As an element inside the <Transition> component is added, we can use these first three classes to animate that transition:
- v-enter-from
- v-enter-active
- v-enter-to
And as an element is removed inside the <Transition> component, we can use the next three classes :
- v-leave-from
- v-leave-active
- v-leave-to
Note: There can only be one element on root level of the <Transition> component.
Now, let's use four of these classes so that we can animate both when the <p> tag is added, and when it is removed.
Example
App.vue:
<template>
<h1>Add/Remove <p> Tag</h1>
<button @click="this.exists = !this.exists">{{btnText}}</button><br>
<Transition>
<p v-if="exists">Hello World!</p>
</Transition>
</template>
<script>
export default {
data() {
return {
exists: false
}
},
computed: {
btnText() {
if(this.exists) {
return 'Remove';
}
else {
return 'Add';
}
}
}
}
</script>
<style>
.v-enter-from {
opacity: 0;
translate: -100px 0;
}
.v-enter-to {
opacity: 1;
translate: 0 0;
}
.v-leave-from {
opacity: 1;
translate: 0 0;
}
.v-leave-to {
opacity: 0;
translate: 100px 0;
}
p {
background-color: lightgreen;
display: inline-block;
padding: 10px;
transition: all 0.5s;
}
</style>
We can also use the v-enter-active and v-leave-active to set styling or animation during adding or during removal of an element:
Example
App.vue:
<template>
<h1>Add/Remove <p> Tag</h1>
<button @click="this.exists = !this.exists">{{btnText}}</button><br>
<Transition>
<p v-if="exists">Hello World!</p>
</Transition>
</template>
<script>
export default {
data() {
return {
exists: false
}
},
computed: {
btnText() {
if(this.exists) {
return 'Remove';
}
else {
return 'Add';
}
}
}
}
</script>
<style>
.v-enter-active {
background-color: lightgreen;
animation: added 1s;
}
.v-leave-active {
background-color: lightcoral;
animation: added 1s reverse;
}
@keyframes added {
from {
opacity: 0;
translate: -100px 0;
}
to {
opacity: 1;
translate: 0 0;
}
}
p {
display: inline-block;
padding: 10px;
border: dashed black 1px;
}
</style>
The Transition 'name' Prop
In case you have several <Transition> components, but you want at least one of the <Transition> components to have a different animation, you need different names for the <Transition> components to tell them apart.
We can choose the name of a <Transition> component with the name prop, and that changes the name of the transition classes as well, so that we can set different CSS animation rules for that component.
<Transition name="swirl">
If the transition name prop value is set to 'swirl', the automatically available classes will now start with 'swirl-' instead of 'v-':
- swirl-enter-from
- swirl-enter-active
- swirl-enter-to
- swirl-leave-from
- swirl-leave-active
- swirl-leave-to
In the example below we use the name prop to give the <Transition> components different animations. One <Transition> component is not given a name, and is therefore given animations using the automatically generated CSS classes starting with 'v-'. The other <Transition> component is given a name 'swirl' so that it can be given rules for animation with the automatically generated CSS classes starting with 'swirl-'.
Example
App.vue:
<template>
<h1>Add/Remove <p> Tag</h1>
<p>The second transition in this example has the name prop "swirl", so that we can keep the transitions apart with different class names.</p>
<hr>
<button @click="this.p1Exists = !this.p1Exists">{{btn1Text}}</button><br>
<Transition>
<p v-if="p1Exists" id="p1">Hello World!</p>
</Transition>
<hr>
<button @click="this.p2Exists = !this.p2Exists">{{btn2Text}}</button><br>
<Transition name="swirl">
<p v-if="p2Exists" id="p2">Hello World!</p>
</Transition>
</template>
<script>
export default {
data() {
return {
p1Exists: false,
p2Exists: false
}
},
computed: {
btn1Text() {
if(this.p1Exists) {
return 'Remove';
}
else {
return 'Add';
}
},
btn2Text() {
if(this.p2Exists) {
return 'Remove';
}
else {
return 'Add';
}
}
}
}
</script>
<style>
.v-enter-active {
background-color: lightgreen;
animation: added 1s;
}
.v-leave-active {
background-color: lightcoral;
animation: added 1s reverse;
}
@keyframes added {
from {
opacity: 0;
translate: -100px 0;
}
to {
opacity: 1;
translate: 0 0;
}
}
.swirl-enter-active {
animation: swirlAdded 1s;
}
.swirl-leave-active {
animation: swirlAdded 1s reverse;
}
@keyframes swirlAdded {
from {
opacity: 0;
rotate: 0;
scale: 0.1;
}
to {
opacity: 1;
rotate: 360deg;
scale: 1;
}
}
#p1, #p2 {
display: inline-block;
padding: 10px;
border: dashed black 1px;
}
#p2 {
background-color: lightcoral;
}
</style>
JavaScript Transition Hooks
Every Transition class as just mentioned corresponds to an event that we can hook into to run some JavaScript code.
| Transition Class | JavaScript Event |
|---|---|
| v-enter-from | before-enter |
| v-enter-active | enter |
| v-enter-to | after-enterenter-cancelled |
| v-leave-from | before-leave |
| v-leave-active | leave |
| v-leave-to | after-leaveleave-cancelled (v-show only) |
When the after-enter event happens in the example below, a method runs that displays a red <div> element.
Example
App.vue:
<template>
<h1>JavaScript Transition Hooks</h1>
<p>This code hooks into "after-enter" so that after the initial animation is done, a method runs that displays a red div.</p>
<button @click="pVisible=true">Create p-tag!</button><br>
<Transition @after-enter="onAfterEnter">
<p v-show="pVisible" id="p1">Hello World!</p>
</Transition>
<br>
<div v-show="divVisible">This appears after the "enter-active" phase of the transition.</div>
</template>
<script>
export default {
data() {
return {
pVisible: false,
divVisible: false
}
},
methods: {
onAfterEnter() {
this.divVisible = true;
}
}
}
</script>
<style scoped>
.v-enter-active {
animation: swirlAdded 1s;
}
@keyframes swirlAdded {
from {
opacity: 0;
rotate: 0;
scale: 0.1;
}
to {
opacity: 1;
rotate: 360deg;
scale: 1;
}
}
#p1, div {
display: inline-block;
padding: 10px;
border: dashed black 1px;
}
#p1 {
background-color: lightgreen;
}
div {
background-color: lightcoral;
}
</style>
You can use the "Toggle" button in the example below to interrupt the enter transition phase of the <p> element so that the enter-cancelled event is triggered:
Example
App.vue:
<template>
<h1>The 'enter-cancelled' Event</h1>
<p>Click the toggle button again before the enter animation is finished to trigger the 'enter-cancelled' event.</p>
<button @click="pVisible=!pVisible">Toggle</button><br>
<Transition @enter-cancelled="onEnterCancelled">
<p v-if="pVisible" id="p1">Hello World!</p>
</Transition>
<br>
<div v-if="divVisible">You interrupted the "enter-active" transition.</div>
</template>
<script>
export default {
data() {
return {
pVisible: false,
divVisible: false
}
},
methods: {
onEnterCancelled() {
this.divVisible = true;
}
}
}
</script>
<style scoped>
.v-enter-active {
animation: swirlAdded 2s;
}
@keyframes swirlAdded {
from {
opacity: 0;
rotate: 0;
scale: 0.1;
}
to {
opacity: 1;
rotate: 720deg;
scale: 1;
}
}
#p1, div {
display: inline-block;
padding: 10px;
border: dashed black 1px;
}
#p1 {
background-color: lightgreen;
}
div {
background-color: lightcoral;
}
</style>
The 'appear' Prop
If we have an element that we want to animate when the page loads, we need to use the appear prop on the <Transition> component.
<Transition appear>
...
</Transition>
In this example, the appear prop starts an animation when the page load for the first time:
Example
App.vue:
<template>
<h1>The 'appear' Prop</h1>
<p>The 'appear' prop starts the animation when the p tag below is rendered for the first time as the page opens. Without the 'appear' prop, this example would have had no animation.</p>
<Transition appear>
<p id="p1">Hello World!</p>
</Transition>
</template>
<style>
.v-enter-active {
animation: swirlAdded 1s;
}
@keyframes swirlAdded {
from {
opacity: 0;
rotate: 0;
scale: 0.1;
}
to {
opacity: 1;
rotate: 360deg;
scale: 1;
}
}
#p1 {
display: inline-block;
padding: 10px;
border: dashed black 1px;
background-color: lightgreen;
}
</style>
Transition Between Elements
The <Transition> component can also be used to switch between several elements, as long as we make sure that only one element is shown at a time with the use of <v-if> and <v-else-if>:
Example
App.vue:
<template>
<h1>Transition Between Elements</h1>
<p>Click the button to get a new image.</p>
<p>The new image is added before the previous is removed. We will fix this in the next example with mode="out-in".</p>
<button @click="newImg">Next image</button><br>
<Transition>
<img src="/img_pizza.svg" v-if="imgActive === 'pizza'">
<img src="/img_apple.svg" v-else-if="imgActive === 'apple'">
<img src="/img_cake.svg" v-else-if="imgActive === 'cake'">
<img src="/img_fish.svg" v-else-if="imgActive === 'fish'">
<img src="/img_rice.svg" v-else-if="imgActive === 'rice'">
</Transition>
</template>
<script>
export default {
data() {
return {
imgActive: 'pizza',
imgs: ['pizza', 'apple', 'cake', 'fish', 'rice'],
indexNbr: 0
}
},
methods: {
newImg() {
this.indexNbr++;
if(this.indexNbr >= this.imgs.length) {
this.indexNbr = 0;
}
this.imgActive = this.imgs[this.indexNbr];
}
}
}
</script>
<style>
.v-enter-active {
animation: swirlAdded 1s;
}
.v-leave-active {
animation: swirlAdded 1s reverse;
}
@keyframes swirlAdded {
from {
opacity: 0;
rotate: 0;
scale: 0.1;
}
to {
opacity: 1;
rotate: 360deg;
scale: 1;
}
}
img {
width: 100px;
margin: 20px;
}
img:hover {
cursor: pointer;
}
</style>
mode="out-in"
In the example above, the next image is added before the previous image is removed.
We use the mode="out-in" prop and prop value on the <Transition> component so that the removal of an element is finished before the next element is added.
Example
In addition to mode="out-in", this example also uses a computed value 'imgActive' instead of the 'newImg' method we used in the previous example.
App.vue:
<template>
<h1>mode="out-in"</h1>
<p>Click the button to get a new image.</p>
<p>With mode="out-in", the next image is not added until the current image is removed. Another difference from the previous example, is that here we use computed prop instead of a method.</p>
<button @click="indexNbr++">Next image</button><br>
<Transition mode="out-in">
<img src="/img_pizza.svg" v-if="imgActive === 'pizza'">
<img src="/img_apple.svg" v-else-if="imgActive === 'apple'">
<img src="/img_cake.svg" v-else-if="imgActive === 'cake'">
<img src="/img_fish.svg" v-else-if="imgActive === 'fish'">
<img src="/img_rice.svg" v-else-if="imgActive === 'rice'">
</Transition>
</template>
<script>
export default {
data() {
return {
imgs: ['pizza', 'apple', 'cake', 'fish', 'rice'],
indexNbr: 0
}
},
computed: {
imgActive() {
if(this.indexNbr >= this.imgs.length) {
this.indexNbr = 0;
}
return this.imgs[this.indexNbr];
}
}
}
</script>
<style>
.v-enter-active {
animation: swirlAdded 0.7s;
}
.v-leave-active {
animation: swirlAdded 0.7s reverse;
}
@keyframes swirlAdded {
from {
opacity: 0;
rotate: 0;
scale: 0.1;
}
to {
opacity: 1;
rotate: 360deg;
scale: 1;
}
}
img {
width: 100px;
margin: 20px;
}
img:hover {
cursor: pointer;
}
</style>
Transition with Dynamic Components
We can also use the <Transition> component to animate switching between dynamic components:
Example
App.vue:
<template>
<h1>Transition with Dynamic Components</h1>
<p>The Transition component wraps around the dynamic component so that the switching can be animated.</p>
<button @click="toggleValue = !toggleValue">Switch component</button>
<Transition mode="out-in">
<component :is="activeComp"></component>
</Transition>
</template>
<script>
export default {
data () {
return {
toggleValue: true
}
},
computed: {
activeComp() {
if(this.toggleValue) {
return 'comp-one'
}
else {
return 'comp-two'
}
}
}
}
</script>
<style>
.v-enter-active {
animation: slideIn 0.5s;
}
@keyframes slideIn {
from {
translate: -200px 0;
opacity: 0;
}
to {
translate: 0 0;
opacity: 1;
}
}
.v-leave-active {
animation: slideOut 0.5s;
}
@keyframes slideOut {
from {
translate: 0 0;
opacity: 1;
}
to {
translate: 200px 0;
opacity: 0;
}
}
#app {
width: 350px;
margin: 10px;
}
#app > div {
border: solid black 2px;
padding: 10px;
margin-top: 10px;
}
</style>
