I disagree, premature optimisation is.
Changing your style of programming to suit what todays JIT does but tomorrow’s may not, in anticipation of performance issues you have not yet encountered is a waste of everyone’s time. No doubt it is valuable in extremely performance sensitive code but that is the extreme minority, especially in the JavaScript world.
If thinking this makes me a “small child” in your mind I’m fine with that.
Premature optimization is the extra effort required to alter work necessary to circumvent guessed optimization pitfalls. In the same breath Knuth advocates always targeting known performance advantages.
Some advice I know you’ll ignore: your tone in the comments here is deeply patronising. You know absolutely nothing about me and yet are entirely comfortable dismissing my perspective as wrong simply because yours must be correct. It’s not an interesting or rewarding way to converse, it makes me want to stop talking to you as soon as I can. Which I’ll be doing here. Have a good weekend.
My best possible free advise: only advocate to what you practice. If, for example, you have never written an application in JavaScript without a framework, such as Angular, then you are an Angular developer not a JavaScript developer. If you speak to something you have never practiced with a presence of authority people with 10, 15, or 20 years experience will be condescending. That is why imposter syndrome is a thing. Its better to get the unexpected honesty from some irrelevant guy online than get hired into a job and either get it in person or worse compensating for a manager with imposter syndrome.
For what it’s worth, I’ve spent years working with the innards of various JS engines, managed deployments of JavaScriptCore inside iOS apps (fun fact: no JIT) and using QuickJS in low resource environments (no JIT there either). There’s an interesting conversation to be had around optimising your code for the JIT, given the different environments we’ve both worked in. But your ego won’t allow it to take place. A shame for all concerned but in my years of development I’ve met plenty like you and I’m well aware that I’m not about to change your mind so I’ll just leave it there.
> The performance benefits are likely to be minimal
This makes me cry, but not a cry of joy or ecstasy. People guessing about performance is perhaps the most frequent anti-pattern in all programming. Please read the following document, you can skip to the end but it may not make much sense if you do.
https://github.com/prettydiff/wisdom/blob/master/JavaScript_...
When developers make random performance assumptions, defensive assumptions are worse, it immediately identifies a lack of professional maturity. Its like small children playing games that expand their imagination, which is great for small children but less great for developers pretending to be adults.