findClosestInBst.js

function findClosestValueInBst(tree, target) {
  return findClosestValueRecursive(tree, target, tree.value);
}

function findClosestValueRecursive(tree, target, closest) {
	if (!tree) return closest;
	if (Math.abs(target - closest) > Math.abs(target - tree.value)) {
		closest = tree.value;
	}
	if (target < tree.value) {
		return findClosestValueRecursive(tree.left, target, closest);
	}
	if (target > tree.value) {
		return findClosestValueRecursive(tree.right, target, closest);
	}
	
	return closest;
}

class BST {
  constructor(value) {
    this.value = value;
    this.left = null;
    this.right = null;
  }
}