How to find a value is present in binary tree or not in JavaScript ?

We are required to write a JavaScript function on the prototype object of a BinarySearchTree data type that takes in a value and finds whether or not that value is contained in the BST.

Example

The code for this will be -

// class for a single Node for BST
class Node {
   constructor(value) {
      this.value = value;
   }
}
// class for BST
// contains function to insert node and search for existing nodes
class BinarySearchTree {
   constructor() {
      this._root = null;
   };
   insert(value) {
      let node = this, side = '_root';
      while (node[side]) {
         node = node[side];
         if (value === node.value) {
            return;
         };
         side = value < node.value ? 'left' : 'right';
      };
      node[side] = new Node(value);
   };
   contains(value) {
      let current = this._root;
      while (current) {
         if (value === current.value) {
            return true;
         };
         current = value < current.value ? current.left : current.right;
      }
      return false;
   };
}
const tree = new BinarySearchTree();
for (let i = 0; i < 10; i++) {
   tree.insert(Math.floor(Math.random() * 1000));
};
tree.insert(34);
console.log(tree.contains(34));
console.log(tree.contains(334));

Output

And the output in the console will be −

true
false