4 Tiny Mistakes That Secretly Kill Your App's Performance

Back from vacation? Great, but your app might have accumulated some subtle yet deadly performance killers while you were away. Like your grandma's Wi-Fi — it kind of works, but the speed reminds you of the dial-up era.

Developer Sylwia Lask compiled four such 'silent assassins': from unnecessary re-renders in React to forgotten Observable subscriptions in Angular. Sounds familiar? Especially when after yet another setInterval in a component, you start suspecting the browser is taking revenge for all those late-night deploys.

Here's a quick checklist of what to look for:

• Unnecessary re-renders — when your component re-renders more often than your CI fails on a Friday evening.
• Memory leaks — forgotten subscriptions and uncleared timers living their own life, like a JIRA board with 47 columns.
• Heavy computations in render — if your component calculates factorial on every sneeze, it's time to consider memoization.
• Unoptimized lists — rendering a thousand items without virtualization is like trying to fit a square peg in a round hole.

METABYTE studio's comment: We've been there too — especially when the client says 'it seems to work' and you see 5000 warnings in the console. If you want your app to fly instead of crawl, give us a shout — we'll tighten the screws.