Look, we’ve all been there. You’re knee-deep in JavaScript code and suddenly have this brilliant idea: “If I just tweak this bit here, surely it’ll run faster!” Before you know it, you’re down a rabbit hole of micro-optimisations, convinced you’re crafting the most efficient code known to humankind.
The Optimisation Itch
It’s tempting. The thought that with just a few clever tricks, you can make your code zoom along at lightning speed. But here’s the kicker: more often than not, these early optimisation efforts are a bit like rearranging deck chairs on the Titanic. They might make you feel productive, but they’re not addressing the real issues. Because if you haven’t even built your app yet, what are you optimising?
Take this simple example:
const numbers = [1, 2, 3, 4, 5];
let sum = 0;
for (let i = 0; i < numbers.length; i++) {
sum += numbers[i];
}“Aha!” you might think. “I’ll cache the length and use a while loop instead. That’ll speed things up!”
const numbers = [1, 2, 3, 4, 5];
let sum = 0;
let i = 0;
const len = numbers.length;
while (i < len) {
sum += numbers[i++];
}But hold your horses. In modern JavaScript engines, the difference is negligible at best. You’ve just made your code harder to read for no real gain.
The Cost of Cleverness
Now, don’t get me wrong. Optimisation isn’t inherently bad. But when we rush into it, we often end up with code that’s harder to understand and maintain. It’s like those people who insist on speaking in nothing but obscure idioms – sure, it might make them feel clever, but it’s annoying for everyone else.
Consider this little gem:
const isEven = num => !(num & 1);
Clever, right? It uses a bitwise operation to check if a number is even. But it’s unclear what this does unless you’re intimately familiar with bitwise operations. Compare that to:
const isEven = num => num % 2 === 0;
It might be a little slower, but it’s crystal clear what’s happening. And in the grand scheme, that clarity is worth far more than any microscopic performance gain.
The Real Cost
The danger of premature optimisation isn’t just that it makes your code harder to read. It’s that it distracts you from the real issues. While you’re fussing about micro-optimisations, you might be missing the actual performance bottlenecks in your application.
It’s like trying to save money by switching to cheaper tea bags when you’re haemorrhaging cash on a yacht you never use. You’re focusing on the wrong thing.
So, What’s the Answer?
Look, I’m not saying never optimise. But before you dive in, ask yourself:
- Is there a performance problem?
- If there is, have I identified where it’s coming from?
- Will this optimisation make a meaningful difference?
If you can’t answer “yes” to all three questions, step away from the optimisation toolkit and focus on writing clear, maintainable code first. Trust me, your future self (and your poor colleagues) will thank you.
Remember, premature optimisation is like Christmas decorations in October—it might seem like a good idea at the time. Still, it will probably annoy everyone and create more work in the long run.
