A Front End Engineer's Manifesto

Not necessarily. I like to view it this way: When you are learning a new language (English, German, Chinese, whatever), in day to day conversations it is useful to know some expressions, idioms, or terms, but you should also know where they come from and how to explain them, and not just how to use them.

Learning what "I'm pissed" means in British english is quite nice but if you say that to an American and responds "Who pissed you?", how are going to teach this person of the use of the word "pissed" in this context?

Similarly, a jQuery-only developer will find it difficult to understand and explain what he meant to do with some piece of code, let's say $.each. A "native speaker", ie. a javascript developer, may be able to offer some advice or corrections, like "you could use Array.forEach in this scenario". (Granted this particular example may not be so good due but you get the point).

Sometimes, knowing things closer to the metal isn't good either. It took me ages to unlearn certain practices and just accept the garbage collector would do its job and I no longer need to think about unallocating memory.

Like all things, this one isn't black and white and it's open to subjectivity. For me though, I feel that the negative side of having knowledge of lower levels of your architectural stack is a hindrance more than it is not.

> this sure sounds a lot like the people who insist that you can't be a good programmer unless you've learned some kind of assembler.

This isn't a very good analogy. JavaScript is a high level language, and jQuery is just a library with features that make it a high level DSL. But when you "write jQuery" you're really writing JavaScript, not some other language, so I don't think the analogy with languages compiled to assembly really makes sense. That being said, I do think that knowing some assembly will not hurt you writing C, and likely will help. Similarly, understanding some of how JS is implemented in browsers won't hurt, and might help you write JS.

It's true that there's almost no limit to how deep the rabbit hole goes. Someone building web apps probably doesn't need to have a degree in electrical engineering, but I don't think this kind of slippery slope argument defends someone using jQuery without knowing JavaScript.

In a grandchild comment you wrote:

> It took me ages to unlearn certain practices and just accept the garbage collector would do its job and I no longer need to think about unallocating memory.

You don't need to explicitly think about unallocating memory, but that doesn't mean your knowledge of manual memory management isn't useful. You do need to be aware of how the GC works if you're working with one. You can still have memory leaks, so how could you possibly debug them if you think the GC is magic?

There's this meme that is floated around HN and elsewhere, that the title "software engineer" is just puffery, because we aren't "real" engineers. I try to avoid this discussion because I think it's mostly stupid, but I can't help touch on it here given the title of this manifesto. I just don't think anyone could seriously call themselves a "front end engineer" if they refuse to learn JavaScript, claiming it's not necessary to use jQuery. Given that the author thinks this title is appropriate, I think the assertion about learning JavaScript is perfectly acceptable.

I'd be interested to hear more about what you think though, and about how the negatives to understanding lower levels of the stack outweigh the benefits. In my (limited) experience, some or more understanding of one or even two "levels down the stack" has never been a net-negative.