I’ve been working on cleaning up my JavaScript code and noticed that my linter keeps suggesting I should change my double equals (==) to triple equals (===) in my conditional statements. For example, when I check something like userInput.trim().length == 0 in my if conditions, it always recommends using === instead.
I’m wondering if there’s actually a speed difference between these two operators? Since my application has lots of comparison checks running frequently, even small performance improvements would add up.
Also curious about cases where no type conversion happens anyway - would === still be faster than == in those situations?
performance doesn’t really matter unless you’re doing millions of comparisons every sec. but === prevents those weird edge cases that can mess you up later. like, null == undefined is true but null === undefined is false. ur linter’s got it right - just use === by default, only use == if u need type coercion.
Yes, there is indeed a difference in performance between ‘==’ and ‘===’ in JavaScript. The strict equality operator ‘===’ does not perform type coercion, making it faster. When using ‘==’, the engine applies the abstract equality algorithm, which involves type conversion even if the value types match.
In my experience with projects where I’ve executed thousands of string comparisons in loops, switching from ‘==’ to ‘===’ resulted in noticeable speed improvements, especially on older browsers. While V8 has seen optimizations, some performance difference remains. Additionally, using ‘===’ helps avoid odd behaviors like ‘0’ == 0 evaluating to true, making the code clearer and easier to maintain—this reliability often outweighs the marginal performance gains.
Yeah, there’s a performance difference but it’s tiny in modern JS engines. I’ve benchmarked this heavily in my apps - === is consistently faster, but we’re talking microseconds per operation. The real win is skipping type coercion completely. What matters more is predictability. I learned this the hard way debugging a payment system where == was matching strings and numbers unexpectedly. Here’s the thing - with ==, the engine checks types first anyway, then decides whether to convert. That’s extra work even if no conversion happens. For your userInput.trim().length example, you’re comparing number to number, so === removes any chance of the engine second-guessing the comparison. Bonus: modern bundlers and minifiers optimize strict equality better than loose equality.