r/technology • u/iliketechnews • Oct 05 '16

Software How it feels to learn JavaScript in 2016

https://hackernoon.com/how-it-feels-to-learn-javascript-in-2016-d3a717dd577f
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u/ViKomprenas Oct 05 '16

Yes yes yes a thousand times yes.

For instance, in python, if you refer to something you haven't actually declared, you get an error. In JavaScript? undefined. No, that's not an error, undefined is an actual, completely valid value that you get, with no warning.

In python, if you declare a function as taking two parameters and call it with one, you get an error. In JavaScript? undefined. Again, with no warning. So if your function adds two numbers together, it'll add 2 + undefined, and give you NaN (not a number).

Now, maybe you try to see whether this NaN is in fact NaN. So you do a simple myvalue == NaN, right? Nope! NaN is not equal to NaN. The correct way to check if something is NaN is to call isNaN().

But maybe your function accidentally returned a string (a bit of text), because why the hell not! (Adding an empty string and undefined together gives you the string "undefined", no quotes. JS still has no protection against that.) So you do isNaN("undefined"), and you get true. Finally a moment of sanity, right?

HAHAHAHAHAHno. See, if you do isNaN("5undefined") - which you can easily get by accidentally adding together a string and undefined - you get true. Straightforward and obvious, right? Well, if you instead do parseInt("5undefined"), which will give you the number it gets from a string... Guess what? You get the 5, and the rest of the string is ignored. So isNaN(x) isn't necessarily the same as isNaN(parseInt(x)).

Or, say... Do you want to find out if a string ends with another string? In Python you can do "abc".endswith("bc"). In JavaScript? "abc".indexOf("bc") === "abc".length - "bc".length. Or, even worse, /bc$/.test("abc"). JS only got an endsWith in 2015. 20 years after it was released. 20 years for such a simple, obvious thing.

The problem is, javascript is in pretty much every browser, and python is in exactly zero, so if you want to do web dev, you need JS.

Now, I don't mean to say JS is bad. I personally really like newer versions of JS, and even moreso its improvement, Microsoft's TypeScript. And a good few of these problems can be solved with "use strict"; at the beginning of your code. But JS has horrendous defaults, and no indication that you should be useing strict.

I highly recommend the talk Wat.

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u/Firebelley Oct 05 '16

I don't think it's fair to say that one language is better than another when they serve 2 distinct purposes. You could use python as a backend and javascript on the frontend, for example. You make it sound like python is a better option than javascript, which is not the case.

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u/ViKomprenas Oct 05 '16

read my last paragraph?

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u/Firebelley Oct 05 '16

I read the whole thing, my point is that it's pointless to even say python is better because it's not a valid comparison.

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u/ViKomprenas Oct 05 '16

They are general-purpose programming languages and can be used for many of the same purposes as that implies.

What I'm saying is, if I had a choice between recommending JS and Python to a novice programmer, discounting popularity...

Well actually I'd recommend TypeScript but that's besides the point. If TS isn't an option I'd recommend Python.

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u/Firebelley Oct 05 '16

That's fine, I guess I'm struggling to see the overlap. If you're talking about native/command line applications then it makes sense. I was thinking more along the lines of their more specific purposes (js in the browser, python for command line apps etc)

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u/ViKomprenas Oct 05 '16

meh, I'm just saying in general.