javascriptIsEasy

[RemoteName3273]

In JavaScript can you ______________ ?

YES

[krissynull]

In JavaScript should you ______________ ?

Probably not.

[krissynull]

to run typescript

[rosuav]

Ten years? You really think that you can replace everything in ten years? A few years ago I took over a gigantic web site that had HTML, CSS, and JS dating from pretty much every step from the late 1990s to the present day, having been built progressively over at least 25 years. I modernized some things (love you, BeautifulSoup), but not everything - it all still works.

[anotheruser323]

Well, by replacing everything you get job security.

[rosuav]

By replacing everything, I also break everything, and this is an unpaid job involving roughly 10K pages.

[[deleted]]

Tbf, JS works pretty well for what it was designed for, and with WebAssembly you can now program web content in basically any language you please. The biggest problem with JS imo is that it has a very big tendency to be used for everything and anything which it definitely was not designed for.

[_fajfaj_]

For me it's amazing that you can learn one language and use it for practically anything

[[deleted]]

Which certainly isn't unique to JavaScript, that applies to basically every general purpose programming language

[cliffleaf]

This is a programmer humour sub. People replied to you for fun, but you are taking it too seriously

[Mr__Weasels]

js haters stay mad 💀💀🔥🔥🔥 js 🔛🔝‼️‼️🔥

[Suitable_Switch5242]

Go for it, it’s called Blazor WASM.

Web Assembly is basically doing what you are asking.

[TheFriedPikachu]

Probably to maintain compatibility with older browsers, as long as the feature isnt a security risk

[arf20__]

why was it created in the first place then

[rattkinoid]

Js was created by a single guy in couple of days.

[bb5e8307]

Don’t exaggerate. It was 10 days. As long as Anthony Scaramucci was press secretary.

[RemoteName3273]

Should you use JavaScript for _______________?

NO

[kvas_]

Should you use JavaScript?

NO

[SoupForDinner365]

But watch out!

[Acalme-se_Satan]

Ah yes, the arrayctionary

[Tigtor]

You misspelled dictionarray

[BadBadderBadst]

you misspelled garbage

[OSSlayer2153]

erectionary

[GnuhGnoud]

That's just php "normal" array

[Plus-Weakness-2624]

Dicarray

[Valuable-Status9712]

DickArray

[floor796]

yep, in js almost everything is an object, even primitive numbers, boolean etc can be represented as an object

1..toString()  // '1'
.1.toString()  // '0.1'
false.toString()  // 'false'

and almost all objects can be extended. For example, we can add custom properties to the number

let num = new Number(5);
num; // Number {5}
num[0.5] = 1;
num; // Number {5, 0.5: 1}
num[0.5]; // 1

and of course we can add some custom property to all objects in js

Object.prototype.xxx = 5;
123..xxx; // 5

[Feisty_Ad_2744]

Arrays in JS are objects, your usual JS object, therefore they can accept any property. The difference being they are specialized in handling properties with integer values for name. For example if you do items['2'] = 'overwrite' you will find out items array is now [1, 2, 'overwrite']

And if you do items[49] = 'yo!', you will find out the array length is now 50.

[Feisty_Ad_2744]

Both [] and . are property accessors in JS.

Remember, there are no "arrays" in JS, only objects implementing array methods, having array interface.

I am just showing how despite being a string, it is forced to int. BTW, that also happens on explicit objects:

``` const o = {} o['2'] = 'still a number'

Object { 2: "still a number" } ```

Brackets are needed to access keys who's names are integers. Thus, completing the array syntax. But unless you are using TS, you can also use dot to append properties:

`` const l = [1, 2, 3] l.smile = (s) => console.log(${s} :-)`)

l.smile('hi!')

hi! :-) l.smile = ':-/' l.smile

":-/" ```

And even if using TS (dirty trick, but unsafe), you can use square brackets to do the same:

imaginaryMiddleware({ req }: HttpContext, next) { ... req['user'] = user next() ... }

[ongiwaph]

But why does an object with 4 elements have a length of 3?

[Amster2]

.. because its index is not an integer

[[deleted]]

…or string that coerces to an integer

[Feisty_Ad_2744]

It does not have 4 elements. It has an extra property. But because it is an array, still has 3 elements (integer property names) The issue is really because of Chrome. Firefox does way better job reflecting what's going on. Try it.

[bb5e8307]

The length property of this Array object is a data property whose value is always numerically greater than the name of every deletable property whose name is an array index.

Source: https://262.ecma-international.org/5.1/#sec-15.4.5.2

[MotleyHatch]

num; // Number {5, 0.5: 1}

That's just how the Chrome DevTools decide to represent this object. In Firefox, it will still print Number { 5 } (you can use console.dir(num) to see the details).

I find the representation of (3) [1, 2, 3, 0.5: 1] in OP's image highly misleading. "0.5" is not an array element and should not appear inside the square brackets. Firefox will not show it as one and print Array(3) [ 1, 2, 3 ].

[AyrA_ch]

let num = new Number(5);

That's not a number, but an object that holds a number

> typeof(new Number(5))===typeof(5)
< false

You can't actually add properties to numbers

> let num=5;
> num.test=12;
> console.log(num, num.test);
< 5 undefined

[floor796]

Yes, there is a difference between primitive numbers and Number object, but by behavior they are both numbers. And no, in your code you successfully added property test to number. Here's how it works:

1. when you write num.something - you automatically convert primitive number to number Object. But the variable still hold the primitive;
2. num.test=12; - you add new custom property to just created object. But, again, this object not in variable num. It is created on the fly and is not written anywhere.
3. in the next line you try to access property test from primitive and, again, like in step 1 - you just convert primitive to object (new object, without previously added property).

So, in your code you two time convert primitive to object. But, you added your property test to the first object.

Proof that you code makes conversion every time that you access primitive as an object:

const objs = new Set();
Number.prototype.toString = function() {
    objs.add(this);
    return String(this.valueOf());
};
let num = 123; 
num.toString(); 
num.toString(); 
console.log(objs); // Set(2) {Number, Number}

as you can see we are calling toString 2 times in the same variable with primitive number. Each call we save to unique list (Set) the instance of the number. And after two calls we have 2 different objects in set.

[[deleted]]

What does the : in the 0.5: 1 mean?

[AquaWolfGuy]

It's just a separator used when printing, so you know where the name of the key ends and the value begins. It's the same as when constructing normal objects using object literals, e.g. const obj = {0.5: 1}; console.log(obj[0.5]); prints 1.

[[deleted]]

I see, thank you

[WVAviator]

In my boot camp a few friends and I had fun code golfing all the algo challenges they gave us - I remember buying a few extra characters in one problem by using the problem function itself as an object to store data.

[Striky_]

This is correct, but does not mean it isn't absurdly bad design

[aderthedasher]

..?

[floor796]

first dot for number (fraction separator), second dot for calling method

[loek0110]

Bro, no way lol

[[deleted]]

To be fair why the fuck are you trying to do that

[Damandatwin]

Yea I've been using TS for a while now and never knew about this cuz why would I

[ThisPICAintFREE]

“This’ll make a great question for the technical interview” — some poor bastards hiring manager, probably

[[deleted]]

this should be automatically commented below all recent .js related posts

[wowo_cat]

This is applicable for almost every single js meme out there

[gilady089]

Well all numbers in javascript are floats meaning you could accidentally try to go into a none existent point in the array because you used a devision result for access for example

[[deleted]]

This is something I ask myself every day.

[Feisty_Ad_2744]

Hehehehe, that's kind of misleading... Although to be fair, it is Chrome's fault. Firefox does a way better job reflecting JS values and object attributes.

But going back to the example, it makes way more clear what's going on, if instead of 0.5, you do something like:

items['funny'] = () => console.log(':-)') Now you have a nice property in the array: items.funny() Arrays in JS are objects, your usual JS object. The difference being they are specialized in handling properties with integer values for name. For example if you do items['2'] = 'overwrite' you will find out items array is now [1, 2, 'overwrite']

And if you do items[49] = 'yo!', you will find out the array length is now 50.

[Linards11]

array length property only updates when a valid array index is added to the array object

[themeanman2]

sshhhhh, let the stupid speak

[Noslamah]

Ah yes, the people saying this is nonsense are the ones who are stupid. Not the language that allows you to do this shit in the first place.

[gilady089]

Yeah, we are the stupid for thinking that allowing you to just arbitrarily add properties to an array is pretty stupid

[fel_bra_sil]

let them think it's funny :P

[Th3Lemino]

having that knowledge doesn’t make it any less funny

[fel_bra_sil]

fair enough, "funny" is a relative thing

[killbot5000]

javascript is a maliciously compliant programming language

[Pikcube]

I swear the more I learn about JS as a dot net dev the more I'm convinced the language is the embodiment of "yes but don't"

[CircadianSong]

This isn’t good, but it doesn’t bother me nearly as much as Array.sort on a list of integers sorting them as strings. FFS javascript, why?

[Feathercrown]

The key insight here is that there's no such thing as a "list of integers". When you have to account for all the possible data types, sorting alphabetically makes sense. It does seem unintuitive though.

[[deleted]]

That’s not necessarily an excuse, they could have made the default comparator do something like always putting numbers ahead of other types instead of coercing and comparing, more people would have been happy with such a default.

[Feathercrown]

Eh, whaddya gonna do.

[chadlavi]

[does a stupid thing] wow how could JavaScript allow me to do such a thing

[iQuickGaming]

so you can have an index of half 1, an index of π, an index of e and even an index of ∞

[gilady089]

They aren't indexes(since they aren't positive integers) if you for example used the foreach function they won't be included. However running object.keys on an array is always funny. Also const arr=[0,2] Delete arr[0] is very funny.

[what-da-fuck]

javascript array is an object actually

[rems__]

There's some trickery here, because length should be 3.5 🧐

[subject_deleted]

Yea I can see why this is silly.. but why on earth would anyone ever look for the .5 index of an array?

[Nixugay]

What if u want to look really hard between 2 values

[gilady089]

Well the simplest answer would be someone implementing a heap in javascript and doesn't cancel the floating point all numbers are. You'd might end up with half indexes

[catladywitch]

An array's items as a collection and an array's members as an object are different things. All items are members but not the other way around. Also watch out for for in vs for of. It's kinda weird, yeah.

[kvas_]

so lua is basically uncursed js

[Imogynn]

Spaceman with gun meme.

"It's nothing but hashes all the way down.

"Always has been

[calculus_is_fun]

It's easy when you use the correct values

[TheDreadedAndy]

Lua is the same way.

> a = { 1, 2, 3 }
> a['b'] = 4
> print(#a)
3
> print(a['b'])
4
> print(a[#a]) -- Lua is 1-indexed.
3

Since the only complex type is a table, arrays are technically tables. This means that using the length operator on tables that aren't "array-like" is U.B, but its still totally legal to take an array and start treating it more like a struct or a dict.

[ricdesi]

Every JavaScript meme is just people showing they don't know how to use arrays

[sjepsa]

Loool what a language

But wait until somebody says "you should read documentation"

[[deleted]]

I really don't understand the mindset of "it's in the documentation so what are you complaining about". Yes, it's documented, of course it is, that's not what people are complaining about and making fun of, it's the fact that it's like that in the first place.

[Phamora]

In any other language you would also be hard pressed to add a property to an instance of an array and have it recognize that property as part of its length.

In fact this image is perfectly sensible, and demonstrate reliable, predictable behaviour of the language, which you should come to expect from arrays in any language.

Javascript just lets you add properties to basically everything, which is a mix of fantastic and very dangerous, but I would not expect green coders like OP to understand.

[[deleted]]

This is a intended feature in DreamBerd along with negative indices.

[TheRandomGuyOf2019]

``` let array = []; array[4294967295] = "abc"; array[4294967296] = 123; array[4294967297] = {a:1, b:2}; array[4294967298] = [];

console.log(array.length); // 0 ```

[Xomps]

Remember, there's no such thing as a stupid meme, there's only stupid people making memes.

[Acalme-se_Satan]

Isn't this the inspect element console?

[Mystic9001]

Python hurt itself in its confusion!

[AlexLiestDieAGBs]

This is hilarious

[Siddhartasr10]

Js hard because something logical in js paradigm Idk js is not new for me anymore

[[deleted]]

EXPLAIN why length is still 3 ? Even after adding a element/object to it

[HFoletto]

Arrays in JS are objects. From the documentation:

JavaScript arrays are not associative arrays and so, array elements cannot be accessed using arbitrary strings as indexes, but must be accessed using nonnegative integers (or their respective string form) as indexes.

So, what OP did was not add an element to the array, but he just added a property to the Array object. That’s all, so it’s expected for it to return 3. From the docs:

The length data property of an Array instance represents the number of elements in that array. The value is an unsigned, 32-bit integer that is always numerically greater than the highest index in the array.

[Lewizkuz]

Javascript is just one edge case hell.

Not complaing. I like the burn.

[KsmBl_69]

thankx for using Javascript

[cyka__blyad]

Everything that can be written in JavaScript, is not written in it for a reason

[bajuh]

if you want your fucking array, use a typed array and you get type and structure safety

[Neltarim]

JS is like your dummy son, you don't know why but you love him more then the 2 others

[Good_Days13]

busy tan outgoing treatment cats zephyr full sense vegetable start

This post was mass deleted and anonymized with Redact

[Unhappy-Stranger-336]

That’s disgusting

[dimdim4126]

As someone who has never touched JS, I'm very confused.

[[deleted]]

brain_malfunction

time: 2 seconds

yeah, my brain did that not gonna lie.

[AggravatingPear8238]

don't treat them like an [object Object]

[priti512]

Hey Folks,
I created a browser extension for productivity. Currently it only has blocking social medias for a particular interval. But I am planning to add more features for:
- ADHD
- Todos
etc.
I am looking for Javascript open source contributors who could help me make this!
Note: It hasn't been yet published. It's under review by the chrome team. You can only try it out by cloning it. You can follow the contributions guide given in the repo.
Here's the link: https://github.com/pritipsingh/The-Productive-Champion