diff --git a/Data-Structures/Linked-List/SingleCircularLinkedList.js.js b/Data-Structures/Linked-List/SingleCircularLinkedList.js.js
index fd50253ad..2ba354191 100644
--- a/Data-Structures/Linked-List/SingleCircularLinkedList.js.js
+++ b/Data-Structures/Linked-List/SingleCircularLinkedList.js.js
@@ -73,25 +73,16 @@ class SinglyCircularLinkedList {
     this.size--
   }
 
-  printData () {
+  printData (output = value => console.log(value)) {
     let count = 0
     let current = this.head
 
-    while (current !== null && count !== this.size) {
-      console.log(current.data + '\n')
+    while (current !== null && count < this.size) {
+      output(current.data)
       current = current.next
       count++
     }
   }
 }
 
-const ll = new SinglyCircularLinkedList()
-
-ll.insert(10)
-ll.insert(20)
-ll.insert(30)
-ll.insert(40)
-ll.insert(50)
-ll.insertAt(5, 60)
-ll.remove(5)
-ll.printData()
+export { SinglyCircularLinkedList }
diff --git a/Data-Structures/Linked-List/SinglyLinkList.js b/Data-Structures/Linked-List/SinglyLinkList.js
index f718962bc..174d341b6 100644
--- a/Data-Structures/Linked-List/SinglyLinkList.js
+++ b/Data-Structures/Linked-List/SinglyLinkList.js
@@ -180,12 +180,12 @@ const LinkedList = (function () {
   }
 
   // Function to view the LinkedList
-  LinkedList.prototype.view = function () {
+  LinkedList.prototype.view = function (output = value => console.log(value)) {
     let currentNode = this.head
     let count = 0
     while (count < this.length) {
       count++
-      console.log(currentNode.element)
+      output(currentNode.element)
       currentNode = currentNode.next
     }
   }
@@ -194,16 +194,4 @@ const LinkedList = (function () {
   return LinkedList
 }())
 
-// Implementation of LinkedList
-const linklist = new LinkedList()
-linklist.add(2)
-linklist.add(5)
-linklist.add(8)
-linklist.add(12)
-linklist.add(17)
-console.log(linklist.size())
-console.log(linklist.removeAt(4))
-linklist.addAt(4, 15)
-console.log(linklist.indexOf(8))
-console.log(linklist.size())
-linklist.view()
+export { LinkedList }
diff --git a/Data-Structures/Queue/CircularQueue.js b/Data-Structures/Queue/CircularQueue.js
index 72ae57272..45e0ce3f2 100644
--- a/Data-Structures/Queue/CircularQueue.js
+++ b/Data-Structures/Queue/CircularQueue.js
@@ -28,7 +28,7 @@ class CircularQueue {
   // REMOVES ELEMENTS
   dequeue () {
     if (this.checkEmpty()) {
-      console.log('UNDERFLOW')
+      // UNDERFLOW
       return
     }
     const y = this.queue[this.front]
@@ -62,15 +62,15 @@ class CircularQueue {
   // Checks if max capacity of queue has been reached or not
   checkOverflow () {
     if ((this.front === 1 && this.rear === this.maxLength) || (this.front === this.rear + 1)) {
-      console.log('CIRCULAR QUEUE OVERFLOW')
+      // CIRCULAR QUEUE OVERFLOW
       return true
     }
   }
 
-  // Prints the entire array
-  display () {
+  // Prints the entire array ('*' represents blank space)
+  display (output = value => console.log(value)) {
     for (let index = 1; index < this.queue.length; index++) {
-      console.log(this.queue[index])
+      output(this.queue[index])
     }
   }
 
@@ -85,24 +85,4 @@ class CircularQueue {
   }
 }
 
-function main () {
-  // Star represents blank space
-  const queue = new CircularQueue(6) // Enter Max Length
-  queue.enqueue(1)
-  queue.enqueue(15)
-  queue.enqueue(176)
-  queue.enqueue(59)
-  queue.enqueue(3)
-  queue.enqueue(55)
-
-  queue.display()
-
-  queue.dequeue()
-  queue.dequeue()
-  queue.dequeue()
-  queue.display()
-
-  console.log(queue.peek())
-}
-
-main()
+export { CircularQueue }
diff --git a/Data-Structures/Queue/Queue.js b/Data-Structures/Queue/Queue.js
index 0b80caace..a15e936e0 100644
--- a/Data-Structures/Queue/Queue.js
+++ b/Data-Structures/Queue/Queue.js
@@ -43,38 +43,11 @@ const Queue = (function () {
   }
 
   // List all the items in the queue
-  Queue.prototype.view = function () {
-    console.log(this.queue)
+  Queue.prototype.view = function (output = value => console.log(value)) {
+    output(this.queue)
   }
 
   return Queue
 }())
 
-// Implementation
-const myQueue = new Queue()
-
-myQueue.enqueue(1)
-myQueue.enqueue(5)
-myQueue.enqueue(76)
-myQueue.enqueue(69)
-myQueue.enqueue(32)
-myQueue.enqueue(54)
-
-myQueue.view()
-
-console.log(`Length: ${myQueue.length()}`)
-console.log(`Front item: ${myQueue.peek()}`)
-console.log(`Removed ${myQueue.dequeue()} from front.`)
-console.log(`New front item: ${myQueue.peek()}`)
-console.log(`Removed ${myQueue.dequeue()} from front.`)
-console.log(`New front item: ${myQueue.peek()}`)
-myQueue.enqueue(55)
-console.log('Inserted 55')
-console.log(`New front item: ${myQueue.peek()}`)
-
-for (let i = 0; i < 5; i++) {
-  myQueue.dequeue()
-  myQueue.view()
-}
-
-// console.log(myQueue.dequeue()); // throws exception!
+export { Queue }
diff --git a/Data-Structures/Stack/Stack.js b/Data-Structures/Stack/Stack.js
index e6b99b40b..59f1a31fe 100644
--- a/Data-Structures/Stack/Stack.js
+++ b/Data-Structures/Stack/Stack.js
@@ -45,28 +45,14 @@ const Stack = (function () {
   }
 
   // To see all the elements in the stack
-  Stack.prototype.view = function () {
-    for (let i = 0; i < this.top; i++) { console.log(this.stack[i]) }
+  Stack.prototype.view = function (output = value => console.log(value)) {
+    for (let i = 0; i < this.top; i++) {
+      output(this.stack[i])
+    }
   }
 
   return Stack
 }())
 
-// Implementation
-const myStack = new Stack()
 
-myStack.push(1)
-myStack.push(5)
-myStack.push(76)
-myStack.push(69)
-myStack.push(32)
-myStack.push(54)
-console.log(myStack.size())
-console.log(myStack.peek())
-console.log(myStack.pop())
-console.log(myStack.peek())
-console.log(myStack.pop())
-console.log(myStack.peek())
-myStack.push(55)
-console.log(myStack.peek())
-myStack.view()
+export { Stack }
diff --git a/Data-Structures/Stack/StackES6.js b/Data-Structures/Stack/StackES6.js
index 6e54bab84..1abafd850 100644
--- a/Data-Structures/Stack/StackES6.js
+++ b/Data-Structures/Stack/StackES6.js
@@ -53,16 +53,5 @@ class Stack {
     return el instanceof Stack
   }
 }
-const newStack = new Stack()
-console.log('Is it a Stack?,', Stack.isStack(newStack))
-console.log('Is stack empty? ', newStack.isEmpty)
-newStack.push('Hello world')
-newStack.push(42)
-newStack.push({ a: 6, b: 7 })
-console.log('The length of stack is ', newStack.length)
-console.log('Is stack empty? ', newStack.isEmpty)
-console.log('Give me the last one ', newStack.last)
-console.log('Pop the latest ', newStack.pop())
-console.log('Pop the latest ', newStack.pop())
-console.log('Pop the latest ', newStack.pop())
-console.log('Is stack empty? ', newStack.isEmpty)
+
+export { Stack }
diff --git a/Data-Structures/Tree/BinarySearchTree.js b/Data-Structures/Tree/BinarySearchTree.js
index 53dca6197..2f9e78ad5 100644
--- a/Data-Structures/Tree/BinarySearchTree.js
+++ b/Data-Structures/Tree/BinarySearchTree.js
@@ -32,13 +32,13 @@ const Node = (function Node () {
   }
 
   // Visit a node
-  Node.prototype.visit = function () {
+  Node.prototype.visit = function (output = value => console.log(value)) {
     // Recursively go left
     if (this.left !== null) {
       this.left.visit()
     }
     // Print out value
-    console.log(this.value)
+    output(this.value)
     // Recursively go right
     if (this.right !== null) {
       this.right.visit()
@@ -115,7 +115,7 @@ const Tree = (function () {
   // Inorder traversal
   Tree.prototype.traverse = function () {
     if (!this.root) {
-      console.log('No nodes are there in the tree till now')
+      // No nodes are there in the tree till now
       return
     }
     this.root.visit()
@@ -124,11 +124,11 @@ const Tree = (function () {
   // Start by searching the root
   Tree.prototype.search = function (val) {
     const found = this.root.search(val)
-    if (found === null) {
-      console.log(val + ' not found')
-    } else {
-      console.log('Found:' + found.value)
+    if (found !== null) {
+      return found.value
     }
+    // not found
+    return null
   }
 
   // Add a new value to the tree
@@ -151,16 +151,4 @@ const Tree = (function () {
   return Tree
 }())
 
-// Implementation of BST
-const bst = new Tree()
-bst.addValue(6)
-bst.addValue(3)
-bst.addValue(9)
-bst.addValue(2)
-bst.addValue(8)
-bst.addValue(4)
-bst.traverse()
-bst.search(8)
-bst.removeValue(3)
-bst.removeValue(8)
-bst.traverse()
+export { Tree }
diff --git a/Data-Structures/Tree/Trie.js b/Data-Structures/Tree/Trie.js
index 4dad3d316..c88e9ec22 100644
--- a/Data-Structures/Tree/Trie.js
+++ b/Data-Structures/Tree/Trie.js
@@ -118,20 +118,4 @@ Trie.prototype.findOccurences = function (word) {
   return node.count
 };
 
-// To test
-(function demo () {
-  const x = new Trie()
-  x.insert('sheldon')
-  x.insert('hello')
-  x.insert('anyword')
-  x.insert('sheldoncooper')
-  console.log(x.findOccurences('sheldon'))
-  x.remove('anything')
-  x.insert('sheldon')
-  console.log(x.findOccurences('sheldon'))
-  console.log(x.findAllWords('sheldon'))
-  x.insert('anything')
-  x.remove('sheldoncooper')
-  console.log(x.contains('sheldoncooper'))
-  console.log(x.findAllWords('sheldon'))
-})()
+export { Trie }