dist-javascript-algorithms-and-data-structures/dist/algorithms/tree/breadth-first-search/breadthFirstSearch.js

Algorithms and data-structures implemented on JavaScript

"use strict";

Object.defineProperty(exports, "__esModule", {
  value: true
});
exports.default = breadthFirstSearch;

var _Queue = _interopRequireDefault(require("../../../data-structures/queue/Queue"));

function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { default: obj }; }

/**
 * @typedef {Object} Callbacks
 * @property {function(node: BinaryTreeNode, child: BinaryTreeNode): boolean} allowTraversal -
 *   Determines whether DFS should traverse from the node to its child.
 * @property {function(node: BinaryTreeNode)} enterNode - Called when DFS enters the node.
 * @property {function(node: BinaryTreeNode)} leaveNode - Called when DFS leaves the node.
 */

/**
 * @param {Callbacks} [callbacks]
 * @returns {Callbacks}
 */
function initCallbacks(callbacks = {}) {
  const initiatedCallback = callbacks;

  const stubCallback = () => {};

  const defaultAllowTraversal = () => true;

  initiatedCallback.allowTraversal = callbacks.allowTraversal || defaultAllowTraversal;
  initiatedCallback.enterNode = callbacks.enterNode || stubCallback;
  initiatedCallback.leaveNode = callbacks.leaveNode || stubCallback;
  return initiatedCallback;
}
/**
 * @param {BinaryTreeNode} rootNode
 * @param {Callbacks} [originalCallbacks]
 */


function breadthFirstSearch(rootNode, originalCallbacks) {
  const callbacks = initCallbacks(originalCallbacks);
  const nodeQueue = new _Queue.default(); // Do initial queue setup.

  nodeQueue.enqueue(rootNode);

  while (!nodeQueue.isEmpty()) {
    const currentNode = nodeQueue.dequeue();
    callbacks.enterNode(currentNode); // Add all children to the queue for future traversals.
    // Traverse left branch.

    if (currentNode.left && callbacks.allowTraversal(currentNode, currentNode.left)) {
      nodeQueue.enqueue(currentNode.left);
    } // Traverse right branch.


    if (currentNode.right && callbacks.allowTraversal(currentNode, currentNode.right)) {
      nodeQueue.enqueue(currentNode.right);
    }

    callbacks.leaveNode(currentNode);
  }
}