When Optimisations Go Wrong: Avoiding Bad Practices in JavaScript Performance Tuning

Performance tuning and optimisation are integral parts of web development today. With users expecting near instantaneous page loads and seamless interactivity, we as developers are constantly looking for ways to make our JavaScript apps faster and more efficient.

However, in the quest for speed and efficiency, it’s easy to go overboard and end up with code that is overly complex, insecure, and ultimately counterproductive. In this article, we’ll look at what types of JavaScript optimisations should be avoided.

Premature Optimisation

Premature optimisation is applying performance tweaks before identifying actual bottlenecks and pain points through profiling and measurement. It leads to wasted effort and complicated code that tries to guess where optimisation is needed.

Signs of premature optimisation include:

• Optimisation small functions or code paths without evidence they are the bottleneck.
• Adding caching layers when the cache hit rate is unclear.
• Guessing where optimisation is needed instead of measuring.

Premature optimisation often distracts from bigger picture issues like algorithms, data structures, and…