ts-toolbelt
Version:
TypeScript's largest utility library
30 lines (29 loc) • 918 B
TypeScript
/**
* Explain to TS which function parameter has priority for generic inference
* @param A to de-prioritize
* @returns `A`
* @example
* ```ts
* import {F} from 'ts-toolbelt'
*
* const fn0 = <A extends any>(a0: A, a1: F.NoInfer<A>): A => {
* return {} as unknown as A // just for the example
* }
*
* const fn1 = <A extends any>(a0: F.NoInfer<A>, a1: A): A => {
* return {} as unknown as A // just for the example
* }
*
* const fn2 = <A extends any>(a0: F.NoInfer<A>, a1: F.NoInfer<A>): A => {
* return {} as unknown as A // just for the example
* }
*
* const test0 = fn0('b', 'a') // error: infer priority is `a0`
* const test1 = fn1('b', 'a') // error: infer priority is `a1`
* const test2 = fn2('b', 'a') // works: infer priority is `a0` | `a1`
* ```
* @see https://stackoverflow.com/questions/56687668
*/
export declare type NoInfer<A extends any> = [
A
][A extends any ? 0 : never];