anztrax

type MyAwaited<T> =  T extends PromiseLike<infer A> ? MyAwaited<A> : T;

/* _____________ Test Cases _____________ */
import type { Equal, Expect } from '@type-challenges/utils'

type X = Promise<string>
type Y = Promise<{ field: number }>
type Z = Promise<Promise<string | number>>
type Z1 = Promise<Promise<Promise<string | boolean>>>
type T = { then: (onfulfilled: (arg: number) => any) => any }

anztrax

/* _____________ Your Code Here _____________ */

type If<C extends boolean, T, F> = C extends true ? T: F

/* _____________ Test Cases _____________ */
import type { Equal, Expect } from '@type-challenges/utils'

type cases = [
  Expect<Equal<If<true, 'a', 'b'>, 'a'>>,
  Expect<Equal<If<false, 'a', 2>, 2>>,

anztrax

type MyReadonly2<T, K extends keyof T = keyof T> = {
  readonly [P in K] :T[P]
} & {
  [P in keyof T as P extends K ? never : P] : T[P]
}

anztrax

type Concat<T extends readonly unknown[], U extends readonly unknown[]> = [...T, ...U]

anztrax

type Includes<T extends readonly any[], U> = 
T extends [infer First, ...infer Rest] 
  ? (
    Equal<First, U> extends true 
    ? true 
    : Includes<Rest, U>
  )
   : false

/* _____________ Test Cases _____________ */

anztrax

type Push<T extends unknown[], U> = [...T, U]

anztrax

type Unshift<T extends unknown[], U> = [U, ...T]

anztrax

type MyParameters<T extends (...args: any[]) => any> = T extends (...any:infer S) => any ? S: any

anztrax

type MyOmit<T, K extends keyof T> = {
  [P in keyof T as P extends K ? never: P] :T[P]
}

anztrax

type DeepReadonly<T> = {
  readonly [K in keyof T]: 
    T[K] extends Function 
       ? T[K]
       : T[K] extends { [K in string] : any}
        ? DeepReadonly<T[K]>: T[K]
}