NonEmptyArray

A type which indicates that an array is not empty.

type NonEmptyArray<T> = [T, ...T[]];

• You can use this to create a function like isNonEmptyArray that checks if an array has at least one element.

Example

function getFirstElement<T>(arr: T[]): T {
  return arr[0];
}

const items: number[] = [];

// Runtime error
getFirstElement([]).toString();

// Type error
const fixItems: NonEmptyArray<number> = [];