Path sum [https://leetcode.com/problems/path-sum]

path_sum.js

/**
 * Definition for a binary tree node.
 * function TreeNode(val, left, right) {
 *     this.val = (val===undefined ? 0 : val)
 *     this.left = (left===undefined ? null : left)
 *     this.right = (right===undefined ? null : right)
 * }
 */
/**
 * @param {TreeNode} root
 * @param {number} targetSum
 * @return {boolean}
 */
var hasPathSum = function(root, targetSum) {
    return recursiveSearch(root, 0, targetSum) === true;
};

var recursiveSearch = function(node, currentValue, targetSum) {
    if (!node) {
        return false;
    }

    currentValue += node.val;

    if (!node.left && !node.right && targetSum === currentValue) {
        return true;
    }

    if (node.left) {
        const leftResult = recursiveSearch(node.left, currentValue, targetSum);

        if (leftResult) {
            return true;
        }
    }
    
    if (node.right) {
        const rightResult = recursiveSearch(node.right, currentValue, targetSum);
        
        if (rightResult) {
            return true;
        }
    }
}