locutus/esm/ruby/Array/last.js

Locutus other languages' standard libraries to JavaScript for fun and educational purposes

export function last(arr, n) {
    // parity verified: Ruby 3.3
    //      discuss at: https://locutus.io/ruby/Array/last/
    //     original by: Kevin van Zonneveld (https://kvz.io)
    //          note 1: Returns the last element, or the last n elements, of the array.
    //       example 1: last(['a', 'b', 'c'])
    //       returns 1: 'c'
    //       example 2: last(['a', 'b', 'c'], 2)
    //       returns 2: ['b', 'c']
    //       example 3: last([])
    //       returns 3: undefined
    if (!Array.isArray(arr)) {
        return undefined;
    }
    if (n === undefined) {
        return arr.at(-1);
    }
    return arr.slice(-n);
}