My Favorite TypeScript Tips and Tricks

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Some neat TypeScript tips and tricks I've learned over the years. Now you know them, too!

[@studiowebselect]

type __Awaited = T extends Promise ? U : T will work and no recursivity

[@LachlanMiller]

Good catch - I've always used the recursive snippet, but it's overkill for what I was demonstrating here.

[@studiowebselect]

@LachlanMiller by the way, I learn so mush from you. Love your videos! Continue your great work

[@LachlanMiller]

Thanks@@studiowebselect ! Trying to get back into a habit of posting content. Knowing people find it useful really motivates me!

[@user-dw2ce5tb1k]

What about nested promises tho. Wont work for those

[@LachlanMiller]

@@user-dw2ce5tb1k Yeah, depends what you want. The recursive solution handles the nested cases. Here's the actual one from TypeScript: gist.github.com/lmiller1990/067b9d296bf5a3b05151437009ad7235

[@siyedyoussef3202]

love this kind of video it open your eyes about some typescript magic keep up the great work

[@LachlanMiller]

Thank you!

[@yassinebenazouz4529]

very helpful thank u ^ ^

[@user-ug8qc6tr6b]

Great content! keep going

[@LachlanMiller]

Thank you, will do s🫡

[@EdwinMartin]

“It isn’t a true constant variable, like it is in other languages” That not true. In C++, Java (final), C# (sealed) and probably others, it works just like JavaScript.

[@LachlanMiller]

My bad, I don't know enough other languages. I guess what I meant was I expect keyword claled "const" to be immutable and, well, constant! Thanks for pointing this out.

[@snatvb]

2:17 - it's tuples

[@LachlanMiller]

It's called a tuple? I thought a tuple was something different, like `type T = [number, string]`. Is this really the same type?

[@snatvb]

​@@LachlanMiller ahhh, maybe I understand you wrong when you use "as const" for array you will get tuple (really strict, with literals in your case), as I get you mean foo[number] - this way to get something from foo it's part of cycles in typescript (keyof works same inside ts) you can use foo[string] as well, or template strings inside recursive types to filter something