BreadthFirstTreeTraversal.js

/*
 Breadth First Tree Traversal or level order traversal implementation in javascript
 Author: @GerardUbuntu
*/

class Node {
 constructor (data) {
 this.data = data
 this.left = null
 this.right = null
 }
}

class BinaryTree {
 constructor () {
 this.root = null
 this.traversal = []
 }

 breadthFirst () {
 const h = this.getHeight(this.root)
 for (let i = 0; i !== h; i++) {
 this.traverseLevel(this.root, i)
 }
 return this.traversal
 }

 // Computing the height of the tree
 getHeight (node) {
 if (node === null) {
 return 0
 }
 const lheight = this.getHeight(node.left)
 const rheight = this.getHeight(node.right)
 return lheight > rheight ? lheight + 1 : rheight + 1
 }

 traverseLevel (node, levelRemaining) {
 if (node === null) {
 return
 }
 if (levelRemaining === 0) {
 this.traversal.push(node.data)
 } else {
 this.traverseLevel(node.left, levelRemaining - 1)
 this.traverseLevel(node.right, levelRemaining - 1)
 }
 }
}

export { BinaryTree, Node }