locutus/ruby/Array/first.js

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

"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
exports.first = first;
function first(arr, n) {
    // parity verified: Ruby 3.3
    //      discuss at: https://locutus.io/ruby/Array/first/
    //     original by: Kevin van Zonneveld (https://kvz.io)
    //          note 1: Returns the first element, or the first n elements, of the array.
    //       example 1: first(['a', 'b', 'c'])
    //       returns 1: 'a'
    //       example 2: first(['a', 'b', 'c'], 2)
    //       returns 2: ['a', 'b']
    //       example 3: first([])
    //       returns 3: undefined
    if (!Array.isArray(arr)) {
        return undefined;
    }
    if (n === undefined) {
        return arr[0];
    }
    return arr.slice(0, n);
}