Javascript programming every day of the week

I've been a working JavaScript developer for many years now, but I've been wanting to learn another programming language all along.

Why multilingual

1. It's generally assumed that any software engineer knows more than one language. HTML and CSS are sometimes argued to be languages, but another programming language is inarguable.


2. I'd like to see how the languages do things differently, and get a better sense for what I think is good and what I like and why.


3. A majority of job ads for what I do are for "full stack" engineers, and thus having an inarguably "backend" language makes me more marketable


4. My impression is that most/all other programming languages out there can DO MATH, which JavaScript notoriously is not really the right language for.

Why Java

1. Honestly, I was headed for Python, but my boss at $COMPANY steered me towards something more prevalent in our backend. It is a good thing to have more codebases I can stare at to see how people solve bugs with Java.


2. Python and Java are in the 2/3 position for most commonly used languages, after JavaScript. Python is more in use in the sciences, and among people who pick a language for love... But Java is the language for creating native apps for Android, and that's cool.


3. Java is definitely multi-threaded, so that will be new and interesting.


4. Java, like Javascript, manages memory for you, and doesn't require you to know what hardware you're running on.


5. I think Java is the most common language for random things like fridges and picture frames? Sounds interesting.

But wait... Is Java connected to Oracle?

Oracle has a stink about it, a stink I was previously unaware of the source of. Was it just that Larry Ellison was a notorious asshole? Or the clunky bad-UX products? Or the institutional corporate taste from working there?

Turns out that part of the stink was directly related to Java the programming language.

History of Java

Java was created before JavaScript, but came on the scene right in the same 1995-ish time period. Java's creator, James Gosling, worked at Sun Microsystems. He worked there right up until 2010, when Oracle treated him poorly after they took over Sun.

Huge stink #1: Oracle vs. Google

Oracle, champing at the bit to monetize Java, sued Google within the first half year after conquering Sun. Google had made their own implementation of Java to be the language of Android. Now, was Google at the time doing the Microsoft/Internet Explorer thing, of adding their own bits to the language without a care for interoperability? Maybe/probably. But that's not the case that ultimately came to the Supreme Court. The Supreme Court heard the case of, "can Oracle's lawyers convince a bunch of boomers who can't send their own email that the basic specs of a language can be copyrighted".

Like, in JavaScript, there are three living engines that read a js file and convert it into machine code that actually runs: v8, in use by node and Chrome and almost everyone; SpiderMonkey, the original engine (much rebuilt) from Mozilla; and whatever Apple is doing. In any of them, when the code Math.max(3,5) is analyzed, it returns 5, because the Math library is part of the definition of JavaScript.

But Oracle was arguing that using the words Math.max was crushing their poor innocent copyright, and anyone who made their own engine would have to pay heartily.

I know we all breathed a sigh of relief when Google's lawyers won, but DAMN that was a slimy attempt from Oracle.

Huge stink #2: trying to charge for JDK 11

In 2018, before they'd lost Google v Oracle, but AFTER they'd released JDK 11, Oracle tried to charge every company who used it on some computer, as if it was Photoshop. I haven't traced how many people were using the Oracle-created flavor of Java vs the open-source flavor, but can you imagine a huge vicious company trying to charge you for the previously-free tools you used to do your job?

They backed away from this at the end of 2021 (perhaps after losing at the Supreme Court?). Now they make Java money just from selling expert help with upgrades and security and such.

OpenJDK is the Java of Record

OpenJDK is only connected to Oracle in that a lot of people who work at Oracle spend time working on it, as far as I can tell.

OpenJDK is licensed under a mutated GPL-ish license that, unlike the GPL, doesn't require anything made with it be GPL also. Still, OpenJDK Java is open-source.

New Java comes into being from OpenJDK committees, where seats are tagged by various companies; seems pretty similar to tc39, the group that makes new JavaScript; perhaps a bit more corporate.

What is bad about Java?

Brief investigation, from people who use Java a lot, suggests that there may be incompatible JSON & date-time libraries between different strains/versions of Java; and maybe Java when used in the wild brings in too many libraries that are hard to update. People who don't use Java a lot probably have other opinions, of course.

SQL: the godzilla of database languages! Knex/Bookshelf: a SQL query builder and a JavaScript ORM that works with it, built by Tim Griesser, supported through the issue tracker for each project at https://github.com/tgriesser/ . The Knex/Bookshelf pair make setting up and querying most of the SQL flavors of databases (Postgres, MySQL, MariaDB, SQLite3, and Oracle) more simple and readable, but I'm going to show the table creation mechanism below that I think is the best combination of the two:( click to see lots of code! )

Two great tastes... ...Not so much.

One part of the Hack Reactor program that my developer friends say is really accurate, in terms of preparing you for the real world, is the "Legacy" project. For four days, you and a team of three to four other people get to build anything you like, using any techs you like. Then comes the "Legacy": for four days, your team picks up another team's project and builds cool stuff out from their starting point. How do they techs they chose work for different people going in a different direction?

In my case, not 100% perfectly. So there was this day that I wasn't sure about how to dynamically generate a dropdown menu with Angular... I tried various methods and they weren't working... Eventually I tried just a straight-up, bog-standard <select></select> tag... Even that didn't show up...!

As you can probably guess from the title, the answer is, MaterializeCSS was not the right fancy CSS framework to use with a constantly shifting thing like Angular. Here's the Stack Overflow answer where someone gives a proper sermon about how MaterializeCSS falls short.

CSS/front-end frameworks make it easier to build a website that shrinks and bends well on a mobile phone, and that looks fine without a lot of poking. In fact, often these days you can look at a website and tell what it was made with, because developers are pretty happy to leave it as it came out of the box. MaterializeCSS is an attempt to look like Google's "Material Design" styles... Same paper-airplane-looking arrow for Submit/Send, etc.

However, apparently, MaterialzeCSS does some of its magic by overwriting normal HTML tags with its own... And any of its own things that require JavaScript to open or drop down or pop up must be initialized when the page loads... And anything that changes after the page loads LIKE SAY when a call to a database returns and populates a dropdown menu with options... Just doesn't happen.

Good times, good times.

You can see the website we worked on here: http://teslalegacy.herokuapp.com/ (If it takes many seconds to load, that's just because we're hosting it for free, and Heroku takes awhile to find it if no one has been there for half an hour). To see the glorious hand-crafted pop-up-div-full-of-checkboxes that I used instead of a drop down menu, you have to log in with GitHub. (Setting up a GitHub account will be worthwhile for you, anyway, but that's a story for another day.)

Woop! I've been silent because, some months back, I got into Hack Reactor Remote. It started Monday, and now I have a better sense of what they mean by their "please don't leak our secrets" note in their initial communications... They even suggested some things that make for possibly good blog posts.

Sidenote: I take paper notes because they served me well in college, and I've got vague impressions of research that indicates that things you hand write are things you remember better. (I should buy myself a notebook instead of doing archaeologically interesting things ie reusing paper that only has one side printed on.)

Next to me is a note of something Robin Kim, our technical mentor, said offhandedly (not his exact words):

When you have a bunch of console.log() reporters in your code to help debug it, include in them some indication of where they're coming from. So, like,

console.log('line 233', thing)

The comma is the separator to use in this instance.

He didn't say what made comma the best.

So this is neat because 1. obviously smart and useful idea and 2. wooo, even advanced coders still use console.log to debug! Putting break points in to the Chrome Dev Tools console has been great, also, but nice to know that Chrome Dev Tools are not necessarily the Only True Path.

Here's one I thought would be simple, which wasn't. The problem is, "return a count of all the vowels (not y) in a string." I thought I'd use regex.exec to capture an array of vowels and find the length of the array... But it only ever returned length 2. I see in the Mozilla Developer Network info page that RexExp.length is 2, but I don't know why I'm getting that here. Can someone troubleshoot?

function VowelCount(str) { 
  var re = /([aeiou])/ig;
  var arr = re.exec(str);
  console.log(arr);
  return arr.length; 
}

console.log(VowelCount('moooo'));

So I pivoted to for loops and came up with this,

function VowelCount(str) { 
  var re = /[aeiou]/i;
  var count = 0;
  for (var i = 0; i < str.length; i++) {
    if (re.test(str.charAt(i))) {
      count += 1;
      console.log(i);
  }
  return count; 
}

This also took some troubleshooting, since the count was wrong when I was using the 'g' flag in the regex. I'm also not sure why that was. Other people I looked at also had mangled looking answers, though of course Matt Larsh has something good,

function VowelCount(str) { 
  var vowels = str.match(/[aeiou]/g);
  return vowels.length;
}

Looks like I need to bone up on str.match.

Challenge 5 was, given a number between 1 and 1000, add up all the numbers inclusive in that set. Obviously I could repurpose Matt Larsh's recursive function to do this, so I did so, and it worked first try. Woo! Though, no one else seems to be doing +=. I wonder if this would be super wrong if I wasn't recursing and thus seeing it only once each function call? Or do they just like num + SimpleAdding(stuff)?

function SimpleAdding(num) {
  if (num === 1) {
    return 1;  
  }
  else {
    return num += SimpleAdding(num - 1);
  }      
}

Challenge 6 was one I hadn't yet solved in Free Code Camp: Capitalize every word in a string. I abandoned a couple different paths while trying for speed, and eventually came up with this answer that seems cludgy:

function LetterCapitalize(str) { 
  var foo = str.split('');
  var bar = [];
  bar.push(foo[0].toUpperCase());
  for(var i = 1; i < foo.length; i++) {
    if (foo[i - 1] === ' ') {
      bar.push(foo[i].toUpperCase());
    }
    else {
      bar.push(foo[i]);
    }    
  }
  console.log(bar.join(''));
  return bar.join('');
}
LetterCapitalize('to see how to enter arguments in JavaScript');

I tried replacing the space in the if statement with /\s/ and that didn't work, nor did /\s/g; I'm not sure why not.

One of my abandoned paths was to do a str.replace(regex, function) but I wasn't getting the function to work... So I was super curious to see what Matt Larsh did, and sure enough he did something cool:

function LetterCapitalize(str) { 
  return str.replace(/\b[a-z]/g,function(c){return c.toUpperCase()});
}

That "\b" was something I thought should exist, but didn't find: the signal for "match a word boundary". I just tried /\b\w/g and that works, too; I suppose his way is better, though, since it limits the capitalization to only things that we absolutely know need capitalizing. Unless if \w includes accented letters and other slightly less usual things? My RegEx skillz are not yet l33t and m4d.

I was just reading my friend Anneke's blog from before she did Hack Reactor. In this post she says

"I’m wrapping my head around Javascript’s call() and apply() methods. These get used a lot, and it’s important to understand just how they work. More immediately, these get used in the Hack Reactor pre-course work that I’m working my way through ..."

That crystallized an opinion in me: I want my learning materials to have opinions, because opinions are context.

Eloquent Javascript presents as a textbook, ie "neutral", but since Marijn Haverbeke is a guy with strong opinions they sometimes leak through and make the book way more valuable to me. Codecademy, on the other hand, just presents one thing after another. Last year I asked Ben-the-housemate to help troubleshooting a switch statement project there, and he had to look up the syntax, despite coding JavaScript every day. He explained that switch statements are almost never used. That kind of thing is gold! I'm happy to learn about switch statements, but knowing what the actual bread and butter of a language is is far more helpful. Anneke passed me the Functional Programming in JavaScript page, where Jafar Husain says,

"[map, filter, concatAll, reduce, & zip] will probably be the most powerful, flexible, and useful functions you'll ever learn."

That's what I'm talking about! I'd love to know enough to be able to debate about what is best in JavaScript. Wrangling in forums (well moderated forums that don't allow personal attacks), or watching such wrangles, is the best way to see all sides of a thing.

I looked at the Hack Reactor suggestions for what one should be able to do before applying, and headed over to http://www.coderbyte.com to try their easy track. They score submissions based not only on correctness, but on time, which is not at all my bag. I think when I saw that a year ago I just turned away, even though a friend suggested doing it on my own time and then pasting the answer in... I might do that in the future.

Their first question was the exact same as I saw last week; reverse a string. I came up with this, which, amusingly, is not what I did last week. It uses the join method of arrays that I was searching for last week, so I'm pleased that knowledge is in me...

function FirstReverse(str) { 
  var hold = [];
  for(var i = str.length - 1; i >= 0 ; i--){
    hold.push(str[i]);
  }
  var foo = hold.join("");
  return foo; 
}

FirstReverse("stuff");           

Also, heeey, check out the respect of spacing in that code block. I thought there were HTML tags about code, and found <code> and thought that was it... Ben the housemate says code isn't really a HTML tag and turned me on to <pre>. Thanks!

Anyway, a good thing about CoderByte: they let you see what other people did, after, answering the socrating question of my friend Catherine about whether I looked at other people's solutions. There's a solution like mine above, but relying on methods of strings and arrays that I wasn't aware of; and that solution lets one do everything in a single line!

function FirstReverse(str) { 
  return str.split('').reverse().join('');
}

Way more elegant.

So, 4 was trivial, which was great: make a function that factorializes numbers. Like, 5! is 1 * 2 * 3 * 4 * 5 = 120.

function factorialize(num) {
for (var i = (num - 1); i > 0; i--) {
num *= i;
}
return num;
}

factorialize(5);

But 5... I feel like I shouldn't have to make my own function that takes an array and jams it all into a single string without commas separating the bits. But the concat stuff I was looking at in the Mozilla Developer Network wasn't working that way (even though their example shows it should. So baffled).

And I feel like there must be some way to not declare like 7 variables... But I couldn't figure out how to chain these methods/functions. Anyway: here it is, a function that checks if a statement is a palindrome (ignoring all the non-letter things! The RegEx stuff was honestly fun learning).

function reverseString(str) {
var reverseStr = '';
for (var i = str.length - 1; i > -1; i--){
reverseStr += str[i];
}
return reverseStr;
}

function arrToRevStr(arr) {
var str = '';
for (var i = arr.length - 1; i > -1; i--){
str += arr[i];
}
return str;
}

function palindrome(str) {
var cleanStrArray = /(\w)/g.exec(str);
var cleanStr = arrToRevStr(cleanStrArray);
var cleanStrLow = cleanStr.toLowerCase();

var reverseStr = reverseString(str);
var cleanReverseStrArray = /(\w)/g.exec(reverseStr);
var cleanReverseStr = arrToRevStr(cleanReverseStrArray);
var cleanReverseStrLow = cleanReverseStr.toLowerCase();

if (cleanStrLow == cleanReverseStrLow) {return true;}
else {return false;}
}

palindrome("eye");


I'm grimly slogging through the Javascript track of Codecademy again. Ticking off the boxes for Free Code Camp. The "address book" bit with Bill Gates etc was particularly annoying. Did they ever explain For/In loops? Every other thing Codecademy does is massively slow and information sparse, and then suddenly they expect you to know For/In?

But! Plus side, the people behind the Free Code Camp Twitter account let me know they're building their own Javascript course, so someday Codecademy will be back in its own box for people who are happy with how it works!

Also, I've been taking breaks by reading the massive "What is Code" article at Bloomberg that was going around a few weeks back. It pointed out a quirk in Javascript that I hadn't seen elsewhere, which you can recreate right now (in at least Chrome and Firefox)... F12 to get the Developer Tools open, go to the Console tab, type in 0.2 + 0.4, hit enter. Answer: 0.6000000000000001

I found this page that explains Floating Point errors in Javascript. The upshot is, the computer stores decimal fractions as binary fractions, and sometimes there's no exact match, so it uses the closest binary fraction it has. And you get around this by rounding. I wonder if this is something that people who code JS for a living do all the time?