Let’s play… Does your code suck? JavaScript Variables Edition

Can you tell which code example is bad? Learn the subtle differences between variables in JavaScript by comparing let vs var.

#javascript #programming #game

[wlockuz]

You had me at "does your code suck".
Yes it does.

[TehKarmalizer]

I mostly watch JS videos like this to continue validating why I don’t do web development.

[tomasmartinez]

I've avoided using var without knowing what it does, but this really helped me understand, thanks!

[mylesbuckley]

Gotta love getting a runtime error for something which can be statically checked.

[stevenclark]

As a C/C++ guy that's a big "Holy shit people live like this?!" thing.

[evanbelcher]

One of the most important lessons I learned early in my career as a SWE was that exceptions are good. The way they were taught in college, I felt like my job was to make sure nothing ever threw an exception and halted so I ended up with try/catches and log messages everywhere. No: if something goes wrong, you want to throw a good exception and let it break

[echoarts]

My personal go-to: use "const" for everything unless you need to mutate/set the value - then use let; even then consider using a new const if you can. Don't touch var like it's got an infection, I can't remember the last time I had to use it.

[DK-oxze]

Ah, the good old days of tricky js interview questions.

[FloWoelki]

i love to use const first and then adjust later with let, if needed (like in Rust, having immutability first and then adjust).

[cinderwolf]

"does your code suck"

I fixed a display issue the other day by adding a 0ms setTimeout.

[andreujuanc]

I can't tell because I can barely see the screen when YouTube puts buttons, labels, and other bs all around and blocks everything.

[theilluminatimember]

I always use let ever since it became popular, but now I see why it got popular. I probably don't even realize how many headaces I've dodged

[micheledelzoppo]

Thanks for letting me know before I end up messing up in the future 😅

[AnastasiyaSoyka]

Praise Cthulhu, and his favorite programming language, JavaScript.

[deepaksurya]

The error is not 'a is not defined' it will be ' can not access a before initialisation '

[ultragigachader]

Good one, I knew the var would hoist but I didn't know the value assignment would be executed after the log. I think even with a 100 years of JS experience one can be surprised from time to time.

[kebien]

The TDZ is temporal, as opposed to scope-based. i.e. You can use your variable before it's defined in code order, as long as by the _time_ hou need it, it's been defined.

function logX() {
console.log(x)
// ☝️ refers to the x below thanks to hoisting
}

let x = 15

logX() // prints 15 just fine

[jasonsimpson]

Is your code JavaScript? Then it sucks.

[jorionedwards]

I know nothing about javascript and just guessed that var does something funky based on my minimal Rust experience.

[MichaelSt]

It’s not the code that sucks at this point it’s JavaScript itself