type-fest/source/last-array-element.d.ts

A collection of essential TypeScript types

/**
Extracts the type of the last element of an array.

Use-case: Defining the return type of functions that extract the last element of an array, for example [`lodash.last`](https://lodash.com/docs/4.17.15#last).

@example
```
import type {LastArrayElement} from 'type-fest';

declare function lastOf<V extends readonly any[]>(array: V): LastArrayElement<V>;

const array = ['foo', 2];

typeof lastOf(array);
//=> number
```

@category Array
@category Template literal
*/
export type LastArrayElement<Elements extends readonly unknown[]>
		= number extends Elements['length']
			? Elements extends ReadonlyArray<infer Element>
				? Element
				: never
			: Elements extends readonly [...any, infer Target]
				? Target
				: never;