Programming

JS will be far more versatile if you learn it well. It's in so many dang things.

The biggest annoyances about JS are some things that exist in Python, so you'll already be familiar with loosely typed systems and mutatable objects (dictionaries/hashes or what ever Python calls 'em).

Other than that, it's mostly that there are a million ways to get the same things done, even something like, "define a class with static and instance-bound functions and properties". Older JS techniques only use scope and the prototype and look like a gross hack. Modern JS has actual class syntax.

It all stems from the constant enhancement of the language. Many, many nice features like proper class syntax and first class modules (no more third party module syntax) came in ES2015, and a sadly small number of front end devs to this day really know them well.

Many web dev tutorials use older style techniques just because they've been around ages. If you learn how the new features are mostly syntax sugar on old styles, you'll be a JS pro in no time.

Go has a much cleaner syntax, and is better suited to its specific niche which is (relatively) low-level BE development. If you are attracted to that niche then Go is an excellent option. Also, Go is almost a default for developing for K8S, which might be another plus.

On the other hand, JS is a more general-use language. It has a very loosey-goosey syntax and lots of weird behaviors. It is applicable on both FE and BE but be aware that in each of those, knowing JS is just a first step, since (for example) for FE development you will also need to know at least one of the major frameworks (React, Vue, Angular etc) as well as the page object model and a ton of other stuff.

Bottom line- usually the language is the tool, not the objective. Figure out what you want to develop, then choose the optimal language to do it with.

If you wanted to do both front and backend development TypeScript + JS/Node would make the most sense, no? I say this as someone who works with and enjoys working with Go almost every day, but there's only so much time to learn new stuff.

I can only say what I would do were I 20 years younger, and that is focus on Rust. I write a ton of Python, JS, and Go. Among them, Go is the most enjoyable and in my view has the best tool chain.

But Rust’s tools are even better. And it is very low level when desired, but you can still write even frontends with great wasm bindings and UI libs.

In the end, it doesn’t really matter. Just write.

As someone else already said, don't overthink the language choice aspect in general. If you learn almost any imperative language with C-like syntax (Go, JS/TS, C#, Java etc), picking up another one in the same "family" to a usable degree will be a very minor hiccup done within a very short time (hours). Sure, there are quirks and special syntax and different collections of built-in features for each one, but as a developer you will likely switch between several anyway and need to look up syntax from time to time - you know that something can be done, but the details how are a bit fuzzy.

For instance, I code mostly in C# and JS/TS, but we have legacy applications written in VB.NET so I often google VB syntax for things that I know how to write in C#. I also occasionally code in C, have dabbled in Fortran, Python and PHP and I'm sure I'm forgetting one or two. SQL and LINQ syntax too of course. What you learn on your developer journey is that something can be done, but remembering the specific implementation in a specific language might be a job better suited for your search engine. That said, of course it's good to start with one language that you know pretty well, but it seems like you're already there with Python.

The real challenge is learning the methodology of building applications, philosophy of OOP, patterns and program/application architecture and frameworks. Language choice is very much secondary to those areas of expertise imo.

Personally though, I am partial to JS/TS as I've used those the longest, they are extremely versatile and frontend development is my favorite area.

I'm not a fan of Go from a language design perspective, but it does have plenty of technical merit (cheap coroutines, compiled) compared to using a scripting language for your backend.

Some pointers on other languages:

• Don't sleep on Java/Kotlin or C# for your backend. They're good languages with powerful, well-developed ecosystems. Kotlin even compiles to JS!
• TypeScript is saner JS. Highly recommended.
• If your backend is CPU-bound, Rust will let you squeeze out every ounce of performance at the cost of a relatively steep learning curve.

Figure out what you want to build first, then pick the best tool for the job. A common fault of JS devs is trying to make it work for every platform and usecase as opposed to learning the best language for that platform.

Syntax wise, JS, specially TS has a great syntax and go is much weirder. I don't care what the haters say. JS syntax is very understandable. And you can see why Rust has borrowed a lot of syntax from TS and JS. And I think knowing js is much more useful,but if you want to build big backends with good performance, go is better.

You can use JS for almost anything, but nothing can be used where JS is mostly used.

IMO the specific language doesn't matter here. Python has JiT compilers, AoT compilers, (proper) coroutine tools, front-end dev tools, everything you could need for dev work, that's why it's so popular, even if none of this is in the standard library.

On the other hand, if you want to learn JS or Go you could use them as well. Last time I checked Go doesn't really have any front end tools/frameworks though.

Of the two I think Go is easier to pick up. Also, if Python is your only exposure to programming, you might be surprised to learn that syntactically, Python is the weird one, not the other way around.

If you decide to go with the NodeJS route and want a rapid development framework, my advice would be to check out NestJS.

Personally i prefer go, but these are pretty standard languages; so learning the in's and out's really isn't all that time consuming (you aren't going to have to change how you think about programming like say rego). Since you have python experience these should be no big deal, but maybe worth playing with a bit if you are trying to get a job in either language and need to cross off that bullet.

As for expanding your learning, i'd try something like functional programming (haskell), or query language like rego above. Neither of these will be great for your resume though.

I‘d say it depends on your motivation and your reasons for learning another language. Do you want to build something in particular? In that case, pick the right tool for the job, as the others have suggested. However, if you want to broaden your horizon, I would suggest to try a language based on another paradigm, e.g. a functional language such as Haskell, ML, or OCaml. Want to see some „pure“ object-oriented language? Then maybe have a look at Smalltalk. The languages I have listed may not be the most widely used in practice, but in my experience, knowing several different programming paradigms makes you a better developer overall.

Learning JavaScript for the frontend is an absolute must! Learn basics of modern js and then start learning c# or java for backend. These languages are great for starting out, have a big community of tools and people which will help you immensely and not to mention tons of job opportunities.

After that you can pick up some fe library like vue.js (personally i think it's the best most intuitive. Saying that as a react dev).

Start building out as you learn tho. Don't wait to complete learning. A simple note taking app with a good FE and a backend with features like auth and a sql db to store data will give you much more learning than tutorials.

You can try C# and see if you like it. You can do frontend in it as well, but C# isn't as popular on frontend as JS, so it will be harder to get a job as frontend dev. But on the backend C#/.NET is the best choice for me.

I personally don't like anything JS related. I would simply recommend Go, but even that is not really my go-to. I found learning Nim quite entertaining, and it's middle -ground between Pyhton and Go, which can also target JS, if you want to.