gistfile1.txt

/**
 * Random Generator Library
 */

const MersenneTwister = require("mersennetwister");

const rndFunc = new MersenneTwister();
// const rndFunc = new MersenneTwister(-5489);
// const rndFunc = Math.random();

/**
 * Randomize (shuffle) JS Array.
 * @param  {Array} arr     -array to be shuffled
 * @param  {Function} rndFunc -random function: MarsenneTwister, ...
 * @return {Array}         -shuffled array
 */
module.exports.shuffleArray = arr => {
    let i;
    let j;
    let temp;
    for (i = arr.length - 1; i > 0; i -= 1) {
        j = Math.floor(rndFunc.random() * (i + 1));
        temp = arr[i];
        arr[i] = arr[j];
        arr[j] = temp;
    }
    return arr;
};

/**
 * MarsenneTwister Random Numbers (https://github.com/pigulla/mersennetwister)
 * Filter amount of numbers from 'arr' using Marsennetwister random generator.
 * @param {Array} arr -array of numbers (or strings) to be filtered
 * @param {Number} amount -amount of numbers (or strings) to be selected from 'arr'
 * @return {Array} -array of randomly selected numbers (or strings)
 */
module.exports.filterMT = (amount, arr) => {
    const arrShuffled = module.exports.shuffleArray(arr, rndFunc);
    // console.log(JSON.stringify(arrShuffled));

    const start = 0;
    const end = amount + start;
    return arrShuffled.slice(start, end); // return part of arrShuffled array from start to end index
};