/**
     * Perform level order traversal for a tree,
     * aka Breadth First Search.
     *
     * @param tree {BinarySearchTree}
     * @returns {boolean|[]}
     */
    function bfs(tree) {
        if (!tree.root) {
            return false;
        }

        return bfsHandler(tree.root);
    }

    function bfsHandler(root) {
        // Use an array as a queue by using some of
        // built-in array functions like push and shift.
        let queue = [];
        // Use an array to track the traversed nodes for
        // printing out using console.
        let traversedNodes = [];

        // Enqueue the root node into the queue.
        queue.push(root);

        while (queue.length) {
            let current = queue[0];
            traversedNodes.push(current);

            if (current.left) {
                queue.push(current.left);
            }

            if (current.right) {
                queue.push(current.right);
            }

            // Dequeue the front element in the queue.
            queue.shift();
        }

        return traversedNodes;
      }