functional-data-structure/finger-tree

import assert from 'assert';

import {node2, node3} from '../../2-node/index.js';

export function nodes(M, list) {
    assert(list.length >= 3 && list.length <= 12);
    const out = [];

    const n = list.length;

    let i = 0;

    switch (n % 3) {
        case 1: {
            out.push(node2(M, list[0], list[1]));
            out.push(node2(M, list[2], list[3]));
            i += 4;
            break;
        }

        case 2: {
            out.push(node2(M, list[0], list[1]));
            i += 2;
            break;
        }

        default: {
            break;
        }
    }

    for (; i < n; i += 3) {
        out.push(node3(M, list[i], list[i + 1], list[i + 2]));
    }

    return out;
}