The Vue 3 Reactivity Trap: Why Large Datasets Crash Your Browser

If you’ve ever loaded a table with 10,000 rows in Vue 3 and watched the browser tab freeze, memory usage spike, and the CPU fan spin up like a jet engine, you’ve fallen into the reactivity trap. Vue 3’s reactivity system, powered by ES6 Proxies, is incredibly elegant. It "just works" for 95% of use cases. But when you start dealing with large datasets—think financial dashboards, log viewers, or complex data grids—that elegance becomes a massive performance bottleneck. In this deep dive, we’ll explore exactly why Vue’s default reactivity chokes on large arrays, how to measure the impact, and the production-ready patterns to fix it. The Naive Approach: Deep Reactivity by Default Let's look at a common scenario. You fetch a large array of objects from an API and store it in a ref . < script setup > import { ref , onMounted } from ' vue ' const logs = ref ([]) onMounted ( async () => { const response = await fetch ( ' /api/system-logs ' ) // Assume this returns 50,000 log objects logs . va