Vue.js is designed for performance, but achieving optimal results requires understanding key aspects of its architecture and applying best practices. Vue's dependency-tracking reactivity system ensures only the components that rely on changed data are updated. Vue also comes with an efficient DOM diffing that minimizes actual DOM updates and it supports asynchronous component loading, reducing the initial bundle size.
However, when developing Vue applications we can run into one of the following problems:
Large Component Trees: Deeply nested components with frequent updates can slow rendering.
Unnecessary Re-renders: Mismanagement of reactive data can trigger unwanted updates.
Heavy Initial Load: Large bundles or unused libraries can increase load times.
Memory Leaks: Improperly managed event listeners or unused refs can degrade performance over time.
To solve the first problem, you can utilize the v-memo which is a built-in directive that can be used to conditionally skip the update of large sub-trees or v-for lists:
<div v-memo="[valueA, valueB]">...</div>
To solve the second problem, you can use the v-once which is a built-in directive that can be used to render content that relies on runtime data but never needs to update:
<span v-once>This will never change: {{msg}}</span>
The third problem might be the most complex as it would require you to scan your whole application for code that can be lazy loaded, removed, delayed, or refactored so that it will be more performant and lighter for the browser. To accomplish this, you could use a bundle analyzer tool that would allow you to discover heavy and non-performing code that needs to be refactored.
For the fourth problem, the most common scenario for a memory leak is adding a window event listener in the initial load of the component but not removing it after the component is unmounted. Make sure to check if you register and unregister event listeners correctly like so:
<script setup>
Import { onMounted, onUnmounted } from ‘vue’
onMounted(() => window.addEventListener('mousemove', doSomething))
onUnmounted(() => window.removeEventListener('mousemove', doSomething))
</script>
See the following articles to learn more about how you can improve the performance of your Vue apps:
How to Maximize Vue.js Performance: 4 Proven Techniques for Faster Web Apps
How To Optimize Performance In Vue Apps
Improving Performance of Nuxt with Lazy Pattern