Path to Sum for Binary Search Trees

pathToSum.js

const hasPathToSum = function(node, targetSum) {
	var sum = 0;

	while(sum !== targetSum) {
		if (!node) {
			break;
		}

		sum += node.datum;

		if (node.datum > targetSum - sum) {
			node = node.left;
		} else {
			node = node.right;
		}
	}

	return sum === targetSum;
};

class BinarySearchTree {
	constructor(datum, left = undefined, right = undefined) {
		this.datum = datum;
		this.left = left;
		this.right = right;
	}
}

/* ----------------------- example usage ----------------------- */

var bst = new BinarySearchTree(3,
	new BinarySearchTree(-1,
		new BinarySearchTree(-5),
		undefined
	),
	new BinarySearchTree(5,
		new BinarySearchTree(4),
		new BinarySearchTree(6))
);

console.log(hasPathToSum(bst, 14));