5 Things I Hate About JavaScript 

I didn't include this, bind, type coercion, let dead zones, or any typical "i hate js." I also didn't include Dates because I am convinced that when it was conceived it was considered the best way to handle dates (have you seen other languages in the mid 90s? It was a literal copy of another library at tha time) But the items I included are truly awful items that are not found in other languages (that i know of)

as Fireship once said: 'JS is a language used exclusively to build things it's not supposed to'

“Any application that can be written in JavaScript will, eventually, be written in JavaScript.” - Jeff Atwood, founder of Stack Overflow, in 2007

5:36 This leads to one of my hot takes. Javascript is just the BASIC of the 2010-2020s. It's an approachable entry point for new programmers and people want to use it for everything, but that leads to it being used for things it has no business being used for. And everyone and their grandmother has their own library/way of doing things/dialect for any given task, which stretches the language beyond its comfortable limits

The regex one has actually screwed me over during my live exams, Luckily I was able to write a shitty function to replace what it was doing, but after the exam when I looked at why it was doing it what it was doing I had the same question, WHY?

Principal Fullstack Lead developer here, 18 years of experience. I found your top things to hate about javascript really interesting and curious! Thanks for sharing! I think, in my personal opinion, that yes, this things can be really cumbersome, and it can lead to really messy situations where you face an additional layer of complexity. And of course, this things can leave you spending hours debugging your code for a piece of code that can be really difficult to find (Like the 'g' operator in the regex). However, the most I hate from Javascript it's a big portion of the community. Don't get me wrong. I've found many many many developers that create a really diverse and collaboratively community that ends up being helpful, thoughtful, and really really good educators about the perks and quirks of Javascript. However, particularly in Javascript and Python, I've also found the most toxic, irreverent and excruciating members I've faced. A few days ago, I found a video in a spanish-speaking channel focused on Javascript developers. The Video title was: "STOP using for cicles". That catched my attention and I went to watch the video. During the video, the presenter mentioned that instead of using "For" to iterate over a cycle, we should do it using a Array.map function, the reason: Legibility. However, during the video, the presenter also mentioned that the use of Array.map function allows you to "execute your code in a immutable way", which seemed kinda odd, because the very fact that you don't modify something during your code execution doesn't make it immutable. In the comments section, I saw one person mentioning how he disagreed with the video, because of multiple things. I added my support to this comment by also mentioning that the video was referring to Immutability when he wasn't actually doing immutability, as well as an improper use of the Array.map function. Not 5 minutes later, I got attacked by one of the people involved on the conversation saying that "Clearly I was just a junior developer that was scared of the Array.map function", and I just mentioned that even that you could achieve the same result using a for or an Array.map function, the Array.map function has much worse performance in terms of memory usage and time complexity. Long story short, I wrote a piece of code to demonstrate how using Array.map performed 28 times slower and could only manage arrays the 1/11 the size in comparison to use a for cicle, not to mention that the Array.map function semantical purpose is to map an object from one type to another, so using a map instead of a for would make the code "harder to read" because the semantics of the code itself. The next day, the youtube channel published a video that was titled: "Do not optimize your code" and pretty much what the video talked about is how nowadays, computers are so powerful that "small" optimizations are unnecessary, using the code I provided in the previous video. To finish up, I just decided to stop wasting my time with someone who's motto is: "Dont optimize your code". The person kept attacking me for around 3 days, trying to pull me into arguments. And although I've found amazing people that makes a great great great community around Javascript, these kinds of interactions are not rare.

callback to Map.prototype.forEach takes (value, key, map) to be in line with Array.prototype.forEach which passes (value, index, array) to its callback. Because indexes for arrays are same thing as keys for maps

This isn't a JavaScript but a node issue. If you spawn a child process in node, and that node process logs so much that it crashes due to running out of memory, the callback in the parent process gets passed an exit code of - not a number - but the JS value `null`... which JSers will know is dangerously close to 0. So anyway Jest hurts sometimes.... Don't log a bunch of stuff in your unit tests.

Sort() defaulting to sorting lexiographically, despite dealing with numbers.

Atwood’s Law: “Any application that can be written in JavaScript, will eventually be written in JavaScript.”

Math.max(); // -Infinity Math.min(); // Infinity

With css at the stage it’s at and faster backend languages, JavaScript should be limited to web carousels and scroll loading.

Silly footgun (and one that does somewhat fall into your type coercion moratorium), but checking whether a variable is undefined vs truthy or falsy as a practice (e.g. foo && ... ) has just caused no end of headaches for my applications in the past. Probably more of a best practices thing and goes back to the community being the problem, but it's still unbelievably aggravating.

1. Regex 2. Buffer/Uint8Array slice 3. Map forEach 4. Bitwise casting to 32 bit signed 5. Community

Clearly, [] is the same as 0. IDK how you'ren't seeing it.

When interfacing JS or TS people from my C++ code what I hate most is that they silently send you json with all kinds of shit in it - that is invisible to them because of JS-sloppyness... Like when they randomly send "empty string" instaed of null, undefined as string and such horrible pieces of shit. My code is having tens of special cases for parsing their fucked up shit :D

You said not to use regex , but what is the other alternative to that?

This got me once: function average(averages: number[]) { return averages.reduce((sum, n) => sum + n) / average.length } we divide by average.length, not averages.length, and average.length is for some reason the number of arguments the function takes.

Lemme add number 6, this keyword with functions When I started to learn I used a normal anonymous function instead of arrow function within a class, i never suffered like that hour all I needed was the arrow function Number 7 threading: the reason why I switched to another lang whenever I needed threading it's pain =(

I wasn't subscribed. I thought I was a subscriber. But I was not. Now I am. I hope you hit 100k soon dude. Love the videos. Awesome show! Great Job!

I completely agree that JavaScript was designed for web UI dev and It should be used that way. Most UI developers don't need bit manipulations anyway. Just because you can develop low level networking stuffs with js, doesn't mean you should do. I think developers nowadays are too lazy to learn another language and keep pushing javascript everywhere. Some people think C/C++ is for old people and JS is cool :D

Not using regex patterns? What's the alternative you guys use?

The best place to use regex is for things that you know for a fact that has a very rigid and predictable pattern. Like repetitive codes and languages. Or just a quick tool for extracting data from large amount of text that you need very often. What regex is really not good at is filtering things that are potentially bad for your purposes.

1:34 What is the alternative to regex? how do you validate input to an API?

objects in js are nightmarish i don't know why anyone would write production grad code using such an unsafe structure

As a library maintainer... my least favorite part of JS is the lack of ECMAScript feature support among the various bundlers and frameworks. The number of issues where "it doesn't work in my React Native app bundled with this new bundling framework that doesn't even say it guarantees support for RN... but for some reason I thought it was your fault so fix it now, slave!" is literally the body of the issue are too damn high... I swear, I tried moving from ES5 to ES6, and people complain about everything. BigInt has been stable and in every browser and NodeJS install under the sun for almost a decade and literally people freaked when I tried to use it and it broke their shit. WHY ARE WE ETERNALLY STUCK AS LIBRARY DEVS ONLY USING ES5!?!?!?!? *pulls out hair* I need a coffee, but it reminds me of JavaScript so I've sworn off the stuff.

The"Bruh" gets me every time! 🤣. Now I need a video on 10 things you Love about rust....Yes....I'm asking for 10 lol. You're hilarious....Your brain oozes with knowledge! Appreciate the value you always give brother! Hope you catch a break with that project you're working on with Netflix lol can't imagine. ~Blessings!

02:58 you can use Uint8Array.prototype.slice.call(buffer,start,end) to always deep copy

The forEach callback receiving the value first allows the programmer to save a few keystrokes in the common case of using only the value and not the key... So, yay! for a little longer keyboard lifespan and one fewer unused argument...

JavaScript: "is slow" Python:

Is it possible to create the C language from Javascript to make Javascript faster?

Array.prototype methods use (value, index, array) order of arguments (reverse of array[index] -> value), you don't always need index of value when iterating over arrays. Objects aren't iterable so "for of" doesn't work for them, only "for in" for iterating over keys only, Object.entries() does give them iterable functionality and neat syntax of destructuring like [key, value].

Gotta say, right off the bat you mentioned the global regex flag and I audibly YELLED after realizing THAT was the reason of some annoying bug in a project I have been working on. Strong start hahaha

Regex is actually pretty amazing if you take some time to learn it properly

setTimeout(f, 0) // f is instantly executed setTimeout(f, Infinity) // f is instantly executed

I built the account creation page for our site, and I used a regex to validate emails. To be fair it's very loose validation to make sure you have some stuff, followed by an @, with some more stuff containing a dot at the end. And I know there's a bunch of bullshit RFC edge cases and I'm sure it doesn't work on at least a few of them but I don't give a shit because nobody uses email addresses like that anyway, and if they do then they should know they aren't welcome.

I’m surprised that Netflix isn’t using erlang or elixir given how good they are for multi connection services. Imagine having to rewrite the whole backend with rust…but I guess you can use wasm so it could all be rust.

I'm working with an API that uses 64bit integers as IDs, I couldn't figure out why all of them were getting rounded for the longest time haha. Gotta love that lost precision.

Man your videos are very entertaining

Banger video tbh

Prime you've uploaded a video working with the rust framework for web dev "Yew", with assembly around is there something like that but for go?

immutability wasn’t really a trend until about 5 years ago, so JS still has a bunch of clunky mutable stuff going on. Another classic one is .sort which mutates the source AND returns it.

I liked it when JS' forEach used value, key. Because in most cases we needed the value instead the key. It would be silly to write .foreach((undefined, value) => ...)when we just needed the value.

found out today the modulo operator doesnt work properly on negatives, and the workaround just looks awful

The module system, especially if you are working with typescript and node. It's a mess, some libraries use common js others ES modules...

not that it necessarily excuses the second issue, but have you heard of the "structuredClone" method?

Don't even know javascript because I am a scientist but I still watched the whole ting.

Those tricky JavaScript interview questions. Man I hate them. When you switch from a different language to JavaScript, you really say 'Why?'

I want that backstory to the Primeagen. 100k special plz.

1. why is REGEX bad ? i was recently working with MQTT a lot and was using it most of the time 2. i never really used Buffer or UintArray API's at all directly. In which cases are these actually needed? Im just doing TS for 2yrs so eli5 please

Prototypes! When you go around Stackoverflow, tutorials, videos. You see it a lot. Just modify the Prototype of the object you are working with. So just change the __proto__ of the array and make it work for you... Not knowing that when you change the prototype of a common type/object, you change it EVERYWHERE not only in your func or lines of code. Maybe not a JS language problem, but more a trap for beginning developers, espcially when not being though wel what the prototype actually is and what it does.

It is not just one or two senior devs that I have had to explain how to remove an event listener in vanilla JS. For some reason, people fail it invariably even after reading the spec. Twice. Or thrice. And people also seem to lack understanding of this. I have been told more than once that webcomponents are nice but it cannot see my context x or assign a listener to button y to use itself because no visibility. Well, just bind. It looks ugly but it is what it is. And I am not even a dev but a consultant who does not do any coding. But still I run a ross devs who know less JS than I do… having to explain a use case for a function closure, or the difference between DOM node types 1 and 3, or why you cannot set :focus state on a non-interactive DOM element without tabindexing it with -1 first, etc. One need not explain pointers to C developers, but JS people are often lacking even the basics.

I don't like using toString or parseInt, it's just to long. Instead I much prefer typing 123 + [] (toString) or "123" - 0 (parseInt)

i've just been bitten by the bitwise operation thing 🤣

Typing window.name in your browser search bar to look for documentation of the global variable name will take you to a twitter account

everytime i watch his vids, my 'imposter syndrom' shows up :D

Shout out Hummus

the riddles on getting nested variables to be validated before nulish coalesing was inveted is something that triggers me a lot... if(a && a.b && a.b.c && a.b.c.d) { // do that }... Other thing my experience with javascript catches me is when you are dealing comparisons that may return 0, because 0 is evaluated to false, how about that: if(a===b) { // do that } where b is 0, // will evaluate to false, and will not proceed. lol

how bout I make a video like "5 Things I Hate Bout ThePrimeagen" how would u like dat Mr.Primeagen

A regex for matching emails is a f'ing nightmare. Email validation is shockingly complicated.

1:33 I shot myself in my foot with the test flopping values. Super frustrating!

1. The language itself 2. The people who use it

Here is another one, you would expect somearray.every(condition) to return true if the condition is true, which works fine untill the array is empty, then it return false, which is very misleading, Same for somearray,some

3:42 bruh, I hate JS as much as anyone here, but you're ignoring something obvious. forEach is usually used for iterating over values, indices are (almost alaways) useless. Image having to write `arr.forEach((_, v) => v)` everytime you want to ignore the index. This is why `for x of array` iterates only over values. You can do: ``` [...Object.entries(arr)] .forEach(([i, v]) => {}) ``` To get the order you expect. Of course, that code has too much boilerplate, so we'll have to wait for the iterator-helpers proposal to reach Stage 4

JavaScript has so many edge cases with weird explanations why something happens that you just literally have to keep track of all of these strange behaviors instead of doing your job. I can't stand it sometimes. You just can't learn JavaScript. It brings the new surprise to me every day. And I have been a frontend developer for 7 years...

Email regex validation is very easy when you learn that the TLD isn't required for emails and symbols like +, - are valid. Knowing the spec halves the regex expression :^)

It not just shoots in your food. It blasts your whole leg away.

Ok, so what’s the backstory of the name? Is that in another video?

what makes me confused is why does JS have bitwise operators and systems level stuff when it was meant for adding function to websites and not system level stuff like OS's. 💀 also bit wise or takes the or value of each bit like in an integer like this 10 can be represented as 1010 9 in binary us 1001 its 1010 | 1001 which means each byte gets to be or so it should be 1 | 1 , 0 | 0, 1 | 0, 0 | 1 1 0 1 1 1011

am i the only one that is now really looking forward to finding out why he goes by ThePrimeagen? even on frontendmasters, while everyone puts their real name on their course, he goes by Primeagen xD

If not using Regrets (RegEx) fpr email than how one should validate email?

i've got a juicy fact that i just learnt about 5 minutes ago: associative arrays are NOT part of javascript. which leads to some hilarious results below. * if you access an array index using a numerical string, it coerces the string into an int. i.e. *a["420"] === a[420]* * _however,_ if it's not a numerical string it treats it as a property of the object. i.e. *a["07"] !== a["7"]* * all indices where you assigned a value (even if that value is `undefined`) WILL return true if you call hasOwnProperty. i.e. *[6,9,4,2,0].hasOwnProperty("4") === true* and even *[6,9,4,2,undefined,0].hasOwnProperty("4") === true* * if you skip an index, it'll fill the indices in between with empty slots (which is somehow different from assigning `undefined` values) so if you call hasOwnProperty on the in-between indices they'll return false (!!). i.e., if you initialise an array *a = [6, 9, 4, 2]; a[5] = 0;* then *a.hasOwnProperty("4") === false* HOWEVER *[6,9,4,2,undefined,0].every((v, i) => v === a[i]) === true* . wtf?? js isn't just too smart by half, it's too smart by half recursively. it's just unbridled genius all the way down.

Wait, you're still working for Netflix??

How do you not use regex? Many times it's the best option, can someone elaborate a bit? thanks EDIT: Found the answer in the comment :)

Yo prime why you gotta publish this the day I interview to become a JS instructor

Number 5 bit me in the ass at the 4th week during development in my first job

Just subbed to get you to 100K!!!! also my first comment ever

Oh no! I wasn't subscribed! Now it's better!

Omg I hate javascript with a vengeance, can't believe it runs 90% of all of a space travelling species software

forEach(val,key) makes sense because most people will use forEach(val) only (for Array at least)

Shallow copying is pure evil. Period. Give us the fast deep clone alternative! No! We have to suffer!

So you suggested we avoid using regex, so what's an alternative to testing a pattern on a string?

ThePrimeagen's gonna carry us to the top, bruh. 2023 is gonna be the year of Rust and NeoVim.

Don't you just love it

Damn, the stateful regex is a thing straight from a nightmare. If it weren't for TypeScript and it's honestly pretty great type system JS would be nearly unusable.

One thing I hate is that you don't have an easy way to compare objects, like { a: 1, b: 2 } === { b: 2, a: 1 } // false :(

how about 5.0 - 2.5 = 2.5000000000000001

what to use in place of regex, exactly? It's ubiquitous

It's not fair. Javascript obviously isn't perfect, but every try to replace Javascript fails. to be fair, you should have a 5 reasons to use Javascript BTW maybe Dart on back end can be blazing fast ( do you believe in this comment or you will make your own benchmark and post on youtube ? )

How would you compare it to Elm?

Well, to this I'd simply had the fact that the overall environment is super tedious to master, with all these config files bundling together, which are annoying to master or even understand, the fact that it doesn't really do multi processing "out of the box" and has a super shitty multiprocessing API even now, the callbacks vs promises mess... And yeah mostly the fact that it's used for everything despite being super slow. Also, the fact that it's a language that has a ton of different versions depending on where and how you use it (node VS chrome VS firefox VS mobile etc.), but well this would be a drawback of other languages as well I guess. Also, the fact that the packages are all centralized in one microsoft-owned repo, the fact that a lot of simple and classic libraries have bugs or archaic parts that are like 5 years old sometimes..

prime is the doc of programmers

Yo prime the foreach gives key value only, if you do Object.entries(OBJECTNAME).foreach((key,value) => console.log(key,value)) am I missing something here ?? Oh it is for map ok sorry I missed that sorry.

yeah i really hate the regex thing, once i tried to use it to parse data from a string, and it didn't work because i need to use matchAll instead of just match with the g flag

Those and more are the reasons I moved to writing Go a few years ago.

Finally someone admits Python supremacy

I am the one about at 0:07 XD

I hate JS, but it's the only way to do web apps and every app has to be a web app since 2010. I'll never escape it.

wheres elixir

you better take this video back javascript is love