Okay, story time.

Back during 2016, I decided to do a little experiment to test the viability of multithreading in a JavaScript server stack, and I'm not talking about the Node.js way of queuing I/O on background threads, or about WebWorkers that box and convert your arguments to JSON and back during a simple call across two JS contexts.

I'm talking about JavaScript code running concurrently on all cores. I'm talking about replacing the god-awful single-threaded event loop of ECMAScript – the biggest bottleneck in software history – with an honest-to-god, lock-free thread-pool scheduler that executes JS code in parallel, on all cores.

I'm talking about concurrent access to shared mutable state – a big, rightfully-hated mess when done badly – in JavaScript.

This rant is about the many mistakes I made at the time, specifically the biggest – but not the first – of which: publishing some preliminary results very early on.

Every time I showed my work to a JavaScript developer, I'd get negative feedback. Like, unjustified hatred and immediate denial, or outright rejection of the entire concept. Some were even adamantly trying to discourage me from this project.

So I posted a sarcastic question to the Software Engineering Stack Exchange, which was originally worded differently to reflect my frustration, but was later edited by mods to be more serious.

You can see the responses for yourself here: https://goo.gl/poHKpK

Most of the serious answers were along the lines of "multithreading is hard". The top voted response started with this statement: "1) Multithreading is extremely hard, and unfortunately the way you've presented this idea so far implies you're severely underestimating how hard it is."

While I'll admit that my presentation was initially lacking, I later made an entire page to explain the synchronisation mechanism in place, and you can read more about it here, if you're interested:

http://nexusjs.com/architecture/

But what really shocked me was that I had never understood the mindset that all the naysayers adopted until I read that response.

Because the bottom-line of that entire response is an argument: an argument against change.

The average JavaScript developer doesn't want a multithreaded server platform for JavaScript because it means a change of the status quo.

And this is exactly why I started this project. I wanted a highly performant JavaScript platform for servers that's more suitable for real-time applications like transcoding, video streaming, and machine learning.

Nexus does not and will not hold your hand. It will not repeat Node's mistakes and give you nice ways to shoot yourself in the foot later, like `process.on('uncaughtException', ...)` for a catch-all global error handling solution.

No, an uncaught exception will be dealt with like any other self-respecting language: by not ignoring the problem and pretending it doesn't exist. If you write bad code, your program will crash, and you can't rectify a bug in your code by ignoring its presence entirely and using duct tape to scrape something together.

Back on the topic of multithreading, though. Multithreading is known to be hard, that's true. But how do you deal with a difficult solution? You simplify it and break it down, not just disregard it completely; because multithreading has its great advantages, too.

Like, how about we talk performance?

How about distributed algorithms that don't waste 40% of their computing power on agent communication and pointless overhead (like the serialisation/deserialisation of messages across the execution boundary for every single call)?

How about vertical scaling without forking the entire address space (and thus multiplying your application's memory consumption by the number of cores you wish to use)?

How about utilising logical CPUs to the fullest extent, and allowing them to execute JavaScript? Something that isn't even possible with the current model implemented by Node?

Some will say that the performance gains aren't worth the risk. That the possibility of race conditions and deadlocks aren't worth it.

That's the point of cooperative multithreading. It is a way to smartly work around these issues.

If you use promises, they will execute in parallel, to the best of the scheduler's abilities, and if you chain them then they will run consecutively as planned according to their dependency graph.

If your code doesn't access global variables or shared closure variables, or your promises only deal with their provided inputs without side-effects, then no contention will *ever* occur.

If you only read and never modify globals, no contention will ever occur.

Are you seeing the same trend I'm seeing?

Good JavaScript programming practices miraculously coincide with the best practices of thread-safety.

When someone says we shouldn't use multithreading because it's hard, do you know what I like to say to that?

"To multithread, you need a pair."

!rant

After over 20 years as a Software Engineer, Architect, and Manager, I want to pass along some unsolicited advice to junior developers either because I grew through it, or I've had to deal with developers who behaved poorly:

1) Your ego will hurt you FAR more than your junior coding skills. Nobody expects you to be the best early in your career, so don't act like you are.

2) Working independently is a must. It's okay to ask questions, but ask sparingly. Remember, mid and senior level guys need to focus just as much as you do, so before interrupting them, exhaust your resources (Google, Stack Overflow, books, etc..)

3) Working code != good code. You are an author. Write your code so that it can be read. Accept criticism that may seem trivial such as renaming a variable or method. If someone is suggesting it, it's because they didn't know what it did without further investigation.

4) Ask for peer reviews and LISTEN to the critique. Even after 20+ years, I send my code to more junior developers and often get good corrections sent back. (remember the ego thing from tip #1?) Even if they have no critiques for me, sometimes they will see a technique I used and learn from that. Peer reviews are win-win-win.

5) When in doubt, do NOT BS your way out. Refer to someone who knows, or offer to get back to them. Often times, persons other than engineers will take what you said as gospel. If that later turns out to be wrong, a bunch of people will have to get involved to clean up the expectations.

6) Slow down in order to speed up. Always start a task by thinking about the very high level use cases, then slowly work through your logic to achieve that. Rushing to complete, even for senior engineers, usually means less-than-ideal code that somebody will have to maintain.

7) Write documentation, always! Even if your company doesn't take documentation seriously, other engineers will remember how well documented your code is, and they will appreciate you for it/think of you next time that sweet job opens up.

8) Good code is important, but good impressions are better. I have code that is the most embarrassing crap ever still in production to this day. People don't think of me as "that shitty developer who wrote that ugly ass code that one time a decade ago," They think of me as "that developer who was fun to work with and busted his ass." Because of that, I've never been unemployed for more than a day. It's critical to have a good network and good references.

9) Don't shy away from the unknown. It's easy to hope somebody else picks up that task that you don't understand, but you wont learn it if they do. The daunting, unknown tasks are the most rewarding to complete (and trust me, other devs will notice.)

10) Learning is up to you. I can't tell you the number of engineers I passed on hiring because their answer to what they know about PHP7 was: "Nothing. I haven't learned it yet because my current company is still using PHP5." This is YOUR craft. It's not up to your employer to keep you relevant in the job market, it's up to YOU. You don't always need to be a pro at the latest and greatest, but at least read the changelog. Stay abreast of current technology, security threats, etc...

These are just a few quick tips from my experience. Others may chime in with theirs, and some may dispute mine. I wish you all fruitful careers!

Evolution of a Programmer

Am I the only one who genuinely hates installers that need internet connection?