Support for NonEmptyArray

[haejunejung]

It provides support for NonEmptyArray.

There are some situations where you need to ensure that an array is not empty before performing operations on it. Using NonEmptyArray helps you handle cases safely.

Here is a detailed example.

const numbersArray: number[] = [];
const getFirstValue = (array: number[]) => array[0];
console.log(getFirstValue(numbersArray) // undefined, there is no type error.

const numbersArray: NonEmptyArray<number> = [] // type error. It should have one or more elements.

const nonEmptyNumbersArray: NonEmptyArray<number> = [1,2,3];
const getFirstValue = (array: NonEmptyArray<number>) => array[0]; // we can handle only the success case.

Here's a detailed. playground.