Print leaf of binary tree

A leaf of binary tree doesn’t have any left & right child. We will use this logic to find leaves.

class Node {
    constructor(value) {
        this.data = value;
        this.left = null;
        this.right = null;
    }
}
class BinaryTree {
    add(value) {
        const node = new Node(value);
        let pointer = this.root;
        if (pointer == null) {
            this.root = node;
        } else {
            while (pointer != null) {
                if (value < pointer.data) {
                    if (pointer.left == null) {
                        pointer.left = node;
                        pointer = null;
                    } else {
                        pointer = pointer.left;
                    }
                } else {
                    if (pointer.right == null) {
                        pointer.right = node;
                        pointer = null;
                    } else {
                        pointer = pointer.right;
                    }
                }
            }
        }
    }
    printLeaves() {
        const print = (node) => {
            if (node == null) {
                return;
            }
            if (node.left == null && node.right == null) {
                console.log("leave", node.data);
            }
            print(node.left);
            print(node.right);
        }
        print(this.root);
    }
}
const tree = new BinaryTree();
tree.add(2);
tree.add(1);
tree.add(3);
tree.printLeaves();