Implement BreadthFirstTreeTraversal in JavaScript (#435)

* Implement BreadthFirstTreeTraversal in JavaScript

* Implement BreadthFirstTreeTraversal in JavaScript

* Implement BreadthFirstTreeTraversal in JavaScript

* Implement BreadthFirstTreeTraversal in JavaScript

Trees/BreadthFirstTreeTraversal.js

@@ -0,0 +1,66 @@
+/*
+  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 = 1; i <= h; i++) {
+      this.traverseLevel(this.root, i)
+    }
+    return this.traversal.toLocaleString()
+  }
+
+  // Compputing the height of the tree
+  getHeight (node) {
+    if (node == null) {
+      return 0
+    } else {
+      const lheight = this.getHeight(node.left)
+      const rheight = this.getHeight(node.right)
+      return lheight > rheight ? lheight + 1 : rheight + 1
+    }
+  }
+
+  traverseLevel (node, level) {
+    if (level === 1 && node !== null) {
+      this.traversal.push(node.data)
+    } else {
+      if (node !== null) {
+        this.traverseLevel(node.left, level - 1)
+        this.traverseLevel(node.right, level - 1)
+      }
+    }
+  }
+}
+
+const binaryTree = new BinaryTree()
+const root = new Node(7)
+root.left = new Node(5)
+root.right = new Node(8)
+root.left.left = new Node(3)
+root.left.right = new Node(6)
+root.right.right = new Node(9)
+binaryTree.root = root
+
+console.log(binaryTree.breadthFirst())
+
+//            7
+//           / \
+//          5   8
+//         / \   \
+//        3   6   9