Created
August 1, 2023 03:11
-
-
Save johan/c29080fd8568853b4abf8a5b62bc0ef8 to your computer and use it in GitHub Desktop.
Some ts utilities handy for well-typed reselect createSelector input functions.
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| /** Constructs a new function type from `F`, instead returning `R` */ | |
| export type Returns<F, R> = F extends (...args: any[]) => infer _ | |
| ? (...args: Parameters<F>) => R | |
| : never; | |
| /** | |
| * Given a (zero-indexed) positional argument number `n` | |
| * and a function call signature generic type `F`, | |
| * produce a well-typed function that selects that `n`th arg. | |
| * @example | |
| * const selectUser = selectArg<(state: Cache, user: User) => void>(1); | |
| */ | |
| export function selectArg<F extends (...args: any[]) => any>( | |
| n: 0 | |
| ): Returns<F, Parameters<F>[0]>; | |
| export function selectArg<F extends (...args: any[]) => any>( | |
| n: 1 | |
| ): Returns<F, Parameters<F>[1]>; | |
| export function selectArg<F extends (...args: any[]) => any>( | |
| n: 2 | |
| ): Returns<F, Parameters<F>[2]>; | |
| export function selectArg<F extends (...args: any[]) => any>( | |
| n: 3 | |
| ): Returns<F, Parameters<F>[3]>; | |
| export function selectArg<F extends (...args: any[]) => any>( | |
| n: 4 | |
| ): Returns<F, Parameters<F>[4]>; | |
| export function selectArg<F extends (...args: any[]) => any>( | |
| n: 5 | |
| ): Returns<F, Parameters<F>[5]>; | |
| export function selectArg<F extends (...args: any[]) => any>( | |
| n: 6 | |
| ): Returns<F, Parameters<F>[6]>; | |
| export function selectArg<F extends (...args: any[]) => any>( | |
| n: 7 | |
| ): Returns<F, Parameters<F>[7]>; | |
| export function selectArg<F extends (...args: any[]) => any>( | |
| n: 8 | |
| ): Returns<F, Parameters<F>[8]>; | |
| export function selectArg<F extends (...args: any[]) => any>( | |
| n: 9 | |
| ): Returns<F, Parameters<F>[9]>; | |
| export function selectArg<F extends (...args: any[]) => any, N extends number>( | |
| n: number | |
| ): Returns<F, Parameters<F>[N]> { | |
| return ((...args) => args[n]) as Returns<F, Parameters<F>[N]>; | |
| } |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment