new INFER features in TypeScript 4.8!

[avi]

The explanation at 5:41 of how the number literal type parsing works in terms of String(Number()) deserves a gold medal for clarity and brevity 🏅

[mmmike]

Ok, so I have one question after all of this, when will I become a typescript alchemist and be able to apply this sort of thing to real projects 😂

[darkmift]

TS has so much depth.
I assumed I had a decent grasp but this is a whole other myriad of subjects.

[BlackxesWasTaken]

This is actually really cool.. but sadly this feature to me at least feels like
"Yeah this is really cool, but I can't think of one situation I would need to use it at compile time rather than runtime"

Great explanation!

[jameshamilton]

Good video! I’m sure the few hundred views you’re getting right now will quickly grow, I’ll be back for more :)

[Xiel]

thanks for the great explanation! made be understand infer better

[michaelangelojong]

You can do the nested example with one infer:

type Test<T> = T extends (...args: any[]) => Promise<Array<infer K extends string>> ? K : never;

type T1 = Test<() => Promise<Array<'cat' | 'dog'>>>; // 'cat' | 'dog'

[jeremiasnater]

I've been a typescript developer for a while now, and im still not finding use cases for most advanced typescript features. In your video you tried to find a real use case and then used Phone numbers that are enbedded inside types which i can't imagine to happen. Phone numbers would be dynamic data, and i still can't see how i could use those types in any way in combination with that dynamic data.

Would anyone mind to explain this use-case or provide me a real useful example of inferring a part of a string-literal type?

[aram]

Need to play with this example, cause P3 might axyually start with zero(s) so, given what you said about the parsing process, the return value would be different (0079 would become 79)...

[TheSysmat]

If input is string in a validation function how would you then construct type X with input string, I don't see point to manually construct type X like that, or I miss something

[arduano]

For your 4.7 example, can't you just do:

type OnlyStringReturnType<T> = T extends (...args: any[]) => Promise<Array<infer S extends string>> ? S : never;

It seems to work fine, unless there's some edge cases?

[SahraClayton]

I really wanted to be a front end developer until I see all this Typescript syntax, i really enjoyed Javascript

[PS-oyxr]

ok cool but how to handle this in real life scenarios? I would be grateful for some scenarios/examples

[gbedumallam]

You voice is good but the background music in the way. Assuming it is at max volume of 10, tone it down to say 1 or 2.

[ChrisAthanas]

Music is distracting and very repetitive

[gidmanone]

Anyone know why Typescript choose to use ternary operator over the more easily understood if-else alternative?

Ternary overly complicates the type system in my opinion. Since nested ternary is bad practice in regular coding.

[dfytq]

Are u here to show what infer is or what u know about infer? 😂 Why people makes video in youtube i don't know.