locutus/esm/php/array/array_rand.js

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

export function array_rand(array, num) {
    //       discuss at: https://locutus.io/php/array_rand/
    //      original by: Waldo Malqui Silva (https://waldo.malqui.info)
    // reimplemented by: Rafał Kukawski
    //        example 1: array_rand( ['Kevin'], 1 )
    //        returns 1: '0'
    // By using Object.keys we support both, arrays and objects
    // which phpjs wants to support
    const keys = Object.keys(array);
    if (typeof num === 'undefined' || num === null) {
        num = 1;
    }
    else {
        num = +num;
    }
    if (isNaN(num) || num < 1 || num > keys.length) {
        return null;
    }
    // shuffle the array of keys
    for (let i = keys.length - 1; i > 0; i--) {
        const j = Math.floor(Math.random() * (i + 1)); // 0 ≤ j ≤ i
        const tmp = keys[j];
        const current = keys[i];
        if (tmp === undefined || current === undefined) {
            return null;
        }
        keys[j] = current;
        keys[i] = tmp;
    }
    return num === 1 ? (keys[0] ?? null) : keys.slice(0, num);
}