stack/packages/mosaic/framework/skills/vue-best-practices/reference/animation-class-based-technique.md

title, impact, impactDescription, type, tags

title	impact	impactDescription	type	tags
Use Class-based Animations for Non-Enter/Leave Effects	LOW	Class-based animations are simpler and more performant for elements that remain in the DOM	best-practice	vue3 animation css class-binding state

Use Class-based Animations for Non-Enter/Leave Effects

Impact: LOW - For animations on elements that are not entering or leaving the DOM, use CSS class-based animations triggered by Vue's reactive state. This is simpler than <Transition> and more appropriate for feedback animations like shake, pulse, or highlight effects.

Task Checklist

• Use class-based animations for elements staying in the DOM
• Use <Transition> only for enter/leave animations
• Combine CSS animations with Vue's class bindings (:class)
• Consider using setTimeout to auto-remove animation classes

When to Use Class-based Animations:

• User feedback (shake on error, pulse on success)
• Attention-grabbing effects (highlight changes)
• Hover/focus states that need more than CSS transitions
• Any animation where the element stays mounted

When to Use Transition Component:

• Elements entering/leaving the DOM (v-if/v-show)
• Route transitions
• List item additions/removals

Basic Pattern

<template>
  <div :class="{ shake: showError }">
    <button @click="submitForm">Submit</button>
    <span v-if="showError">This feature is disabled!</span>
  </div>
</template>

<script setup>
import { ref } from 'vue';

const showError = ref(false);

function submitForm() {
  if (!isValid()) {
    // Trigger shake animation
    showError.value = true;

    // Auto-remove class after animation completes
    setTimeout(() => {
      showError.value = false;
    }, 820); // Match animation duration
  }
}
</script>

<style>
.shake {
  animation: shake 0.82s cubic-bezier(0.36, 0.07, 0.19, 0.97) both;
  transform: translate3d(0, 0, 0); /* Enable GPU acceleration */
}

@keyframes shake {
  10%,
  90% {
    transform: translate3d(-1px, 0, 0);
  }
  20%,
  80% {
    transform: translate3d(2px, 0, 0);
  }
  30%,
  50%,
  70% {
    transform: translate3d(-4px, 0, 0);
  }
  40%,
  60% {
    transform: translate3d(4px, 0, 0);
  }
}
</style>

Common Animation Patterns

Pulse on Success

<template>
  <button @click="save" :class="{ pulse: saved }">
    {{ saved ? 'Saved!' : 'Save' }}
  </button>
</template>

<script setup>
import { ref } from 'vue';

const saved = ref(false);

async function save() {
  await saveData();
  saved.value = true;
  setTimeout(() => (saved.value = false), 1000);
}
</script>

<style>
.pulse {
  animation: pulse 0.5s ease-in-out;
}

@keyframes pulse {
  0%,
  100% {
    transform: scale(1);
  }
  50% {
    transform: scale(1.05);
  }
}
</style>

Highlight on Change

<template>
  <div :class="{ highlight: justUpdated }">Value: {{ value }}</div>
</template>

<script setup>
import { ref, watch } from 'vue';

const value = ref(0);
const justUpdated = ref(false);

watch(value, () => {
  justUpdated.value = true;
  setTimeout(() => (justUpdated.value = false), 1000);
});
</script>

<style>
.highlight {
  animation: highlight 1s ease-out;
}

@keyframes highlight {
  0% {
    background-color: yellow;
  }
  100% {
    background-color: transparent;
  }
}
</style>

Bounce Attention

<template>
  <div :class="{ bounce: needsAttention }" @animationend="needsAttention = false">
    <BellIcon />
  </div>
</template>

<script setup>
import { ref } from 'vue';

const needsAttention = ref(false);

function notifyUser() {
  needsAttention.value = true;
  // No setTimeout needed - using animationend event
}
</script>

<style>
.bounce {
  animation: bounce 0.5s ease;
}

@keyframes bounce {
  0%,
  100% {
    transform: translateY(0);
  }
  50% {
    transform: translateY(-10px);
  }
}
</style>

Using animationend Event

Instead of setTimeout, use the animationend event for cleaner code:

<template>
  <div :class="{ animate: isAnimating }" @animationend="isAnimating = false">Content</div>
</template>

<script setup>
import { ref } from 'vue';

const isAnimating = ref(false);

function triggerAnimation() {
  isAnimating.value = true;
  // Class is automatically removed when animation ends
}
</script>

Composable for Reusable Animations

// composables/useAnimation.js
import { ref } from 'vue';

export function useAnimation(duration = 500) {
  const isAnimating = ref(false);

  function trigger() {
    isAnimating.value = true;
    setTimeout(() => {
      isAnimating.value = false;
    }, duration);
  }

  return {
    isAnimating,
    trigger,
  };
}

<script setup>
import { useAnimation } from '@/composables/useAnimation';

const shake = useAnimation(820);
const pulse = useAnimation(500);
</script>

<template>
  <button :class="{ shake: shake.isAnimating.value }" @click="shake.trigger()">Shake me</button>

  <button :class="{ pulse: pulse.isAnimating.value }" @click="pulse.trigger()">Pulse me</button>
</template>

Reference

• Vue.js Animation Techniques - Class-based Animations
• CSS Animations MDN