binary-search-tree/red-black-tree

import assert from 'assert';

import Node from '../types/Node.js';

/**
 * Computes the sibling of the input node.
 *
 * @param {Node} node - The input node.
 * @returns {Node}
 */
const sibling = (node) => {
    assert(node instanceof Node);
    // We only use this function when node HAS a non-leaf sibling.
    assert(node.parent !== null);

    return node === node.parent.left ? node.parent.right : node.parent.left;
};

export default sibling;