JavaScript array length is weird

[siamekanto]

That's what it's supposed to do, isn't it?

[NHCH]

Weird? It's the most logical thing js has lmao

[lejames]

That's not weird. What's weird would be setting the length to 5, then the program adds 'pear' and 'strawberry' to the array.

[tibebetech]

this is actually a very good feature helping manage array length dynamic

[nothingisreal]

Under the hood the array has to reserve memory. You can either reallocate the memory at ever add OR right aways allocate memory for e.g. 10 elements and then simply set them, which is supposing to be faster. The problem with script "kiddies" is: they never learn how this is ACTUALLY being implemented under the hood. If you learn programming in C or PASCAL you would understand that a collection either needs to dynamically allocate and move memory or use something like linked lists. Linked lists don't require reallocation but are SLOW. Continuous memory (array) is very fast but if you if you want an element that will require to grow the allocated memory this is costly. So typically a strategy to implement this to allocate more memory right away to avoid reallocation. In C#: arrays are fixed size. List has an option to specify a capacity but the size is dynamic (and internally a list is implemented as an array).

[dave]

Ugh, I just found out recently you can assign values to negative indices and JS is just like, “sure thing, buddy 👍”

[electricengine]

the empty items are just properties on the array that dont even exist, thats why theyre not undefined but return undefined when you index them
just like an object key

[muneeburrehman]

C/C++ developers having a stroke rn. 🤣

[devvy]

This isn’t weird, but it’s something I’ve never thought of. I will keep this in mind. I’ve been coding in js for 4 years lol

[adamandsteve]

I tried to learn javascript after languages like c#, c++. It just doesn't make sense. It makes! But when I found out TypeScript it became so much better.

[nalbertcerqueira]

its like CHAR, the length is fixed but if you doesnt use all spaces in the array, they will show empty fields but with memory allocated

[goranjosic]

Whole JS is weird! I started learning it after learn Python quite well, and it was funny to me how much illogic there is in this language

[gokhanburhan]

If you give static array number it does allocate the memory but doesnt put any value in there

[dom]

Whats weird? Was expecting something unlogical, but this was incredibly easy to understand

[wlockuz]

This is a certainly an unconventional feature, its there for backwards compatibility, but I never had any issues with it because in my many years of coding with js I never had a scenario where I needed to assign a value to .length

If you want something actually weird, you should look at how js spec handles the regex with global flag. Its one of the worst pitfalls of working with regex on js.

[AlexAnie-uznr]

This video is beautiful. I enjoyed watching it.

Thanks

[milantornier]

That’s the behavior I would expect tbh.

[loctite]

Imagine that they turned .length into a read-only and every single js framework dont work anymore

[VideoDarslar]

This glitch shows we are living in the matrix 😊

[AvenDonn]

In the grim dark of the 3rd millennium, there is only javascript