Data Structures: Use Breadth First Search in a Binary Search Tree

Data Structures/bstDFS.js

@@ -0,0 +1,54 @@
+// https://www.freecodecamp.org/learn/coding-interview-prep/data-structures/use-depth-first-search-in-a-binary-search-tree
+
+var displayTree = (tree) => console.log(JSON.stringify(tree, null, 2));
+function Node(value) {
+  this.value = value;
+  this.left = null;
+  this.right = null;
+}
+function BinarySearchTree() {
+  this.root = null;
+  // Only change code below this line
+  this.inorder = () => {
+    if (this.root === null) {
+      return null;
+    }
+    const values = [];
+    const traverse = (node) => {
+      if (node.left !== null) traverse(node.left);
+      values.push(node.value);
+      if (node.right !== null) traverse(node.right);
+    };
+    traverse(this.root);
+    return values;
+  };
+
+  this.preorder = () => {
+    if (this.root === null) {
+      return null;
+    }
+    const values = [];
+    const traverse = (node) => {
+      values.push(node.value);
+      if (node.left !== null) traverse(node.left);
+      if (node.right !== null) traverse(node.right);
+    };
+    traverse(this.root);
+    return values;
+  };
+
+  this.postorder = () => {
+    if (this.root === null) {
+      return null;
+    }
+    const values = [];
+    const traverse = (node) => {
+      if (node.left !== null) traverse(node.left);
+      if (node.right !== null) traverse(node.right);
+      values.push(node.value);
+    };
+    traverse(this.root);
+    return values;
+  };
+  // Only change code above this line
+}