Add a value to a Binary Tree.

binary-tree-insert.js

import Node from 'binary-tree-node';

class BinaryTree {
  constructor() {
    this.root = new Node();
  }
  
  // ... other methods
  
  add(value) {
		var node = this.root;
		if (isUndefined(node.value)) {
			node.value = value;
		} else {
			while (!isUndefined(node)) {
				if (isEqualTo(value, node.value)) {
					break; // short-circuit duplicate values
				} else if (value < node.value) {
					if (isUndefined(node.left)) {
						node.left = new Node(value);
						break;
					} else {
						node = node.left;
					}
				} else if (value > node.value) {
					if (isUndefined(node.right)) {
						node.right = new Node(value);
						break;
					} else {
						node = node.right;
					}
				}
			}
		}
		return this;
	};
}

binary-tree-node.js

export default class Node {
	constructor(value, left, right) {
		this.value = value;
		this.left = left;
		this.right = right;
	}
}