NthParameter

Since 1.1.0

Get the Nth parameter type (0-indexed).

Signature

type NthParameter<T, N extends number> = T extends (...args: infer P) => any ? P[N] : never

Parameters

Parameter	Description
T	The function type
N	The parameter index (0-indexed)

Examples

Basic Usage

import type { NthParameter } from 'uni-types'

type Fn = (a: string, b: number, c: boolean) => void

type First = NthParameter<Fn, 0>   // string
type Second = NthParameter<Fn, 1>  // number
type Third = NthParameter<Fn, 2>   // boolean

Extract Specific Parameters

type FetchFn = (url: string, options: RequestInit, callback: () => void) => void

type Url = NthParameter<FetchFn, 0>      // string
type Options = NthParameter<FetchFn, 1>  // RequestInit
type Callback = NthParameter<FetchFn, 2> // () => void

Related

• Parameters - Get all parameters as tuple