random_group2.html

<script src="random_groups2.js"></script>

random_groups2.js

let split_to_groups = function (source, n) {
    const items = source.slice();

    const arr = [];
    for (let i = 0; i < n; i++) {
        arr.push([]);
    }

    let next = 0;
    while (items.length) {
        const i = Math.floor(Math.random() * items.length);
        arr[next].push(items[i]);
        items.splice(i, 1);
        next = (next + 1) % arr.length;
    }
    return arr;
};



function testProgram() {
    "use strict";

    const TEST_DATA = "a b c d e f g h i j";
    const groups = split_to_groups(TEST_DATA.split(' '), 3);

    console.log(groups);

    for (let group of groups) {
        console.log(group);
    }

    console.assert(groups[0].length === 4);
    console.assert(groups[1].length === 3);
    console.assert(groups[2].length === 3);

    const groups_str = groups.reduce((a, x) => a.concat(x), []).sort().join(" ");
    console.log(groups_str);

    console.assert(groups_str === TEST_DATA);

    console.log("OK");

}

testProgram();

console.log(`abc ${123+456}`);