add Queue data structure implementation and test suits

src/dataStructures/Queue.js

@@ -0,0 +1,56 @@
+class Queue {
+  constructor() {
+    this.dataStore = [];
+  }
+
+  /**
+   * @name enqueue
+   * @param {String} elem
+   * @description
+   * handler function which will add new element in queue
+   */
+  enqueue(element) {
+    this.dataStore.push(element);
+  }
+
+  /**
+   * @name dequeue
+   * @description
+   * handler function which will remove element from queue
+   * @returns {String} RemoveElement
+   */
+  dequeue() {
+    return this.dataStore.shift();
+  }
+
+  /**
+   * @name front
+   * @description
+   * handler function which provide the first element in queue
+   * @returns {String} FrontElement
+   */
+  front() {
+    return this.dataStore[0];
+  }
+  /**
+   * @name back
+   * @description
+   * handler function which provide the last element in queue
+   * @returns {String} BackElement
+   */
+  back() {
+    return this.dataStore[this.dataStore.length - 1];
+  }
+  /**
+   * @name empty
+   * @description
+   * handler function which will clear queue
+   * @returns {Array} EmptyQueue
+   */
+  empty() {
+    this.dataStore = [];
+    return this.dataStore;
+  }
+}
+
+module.exports = Queue;

src/dataStructures/Stack.js

@@ -0,0 +1,58 @@
+class Stack {
+  constructor() {
+    this.top = 0;
+    this.dataStore = [];
+  }
+  /**
+      * @name push
+      * @param {String} elem
+      * @description
+      * handler function which will add new element in stack and increament top value by 1
+      */
+  push(element) {
+    this.dataStore[this.top++] = element;
+  }
+  /**
+      * @name pop
+      * @param {String} elem 
+      * @description
+      * handler function which will remove element in stack and decreament top value by 1
+      * @returns {String} RemoveElement
+      */
+  pop() {
+    this.top--;
+    return this.dataStore.pop()
+  }
+  /**
+    * @name peek
+    * @param {String} elem 
+    * @description
+    * handler function which provide the top element on stack
+    * @returns {String} TopElement
+    */
+  peek() {
+    return this.dataStore[this.top - 1];
+  }
+  /**
+    * @name length
+    * @param {String} elem 
+    * @description
+    * handler function which provide the length on element
+    * @returns {Number}
+    */
+  length() {
+    return this.top;
+  }
+  /**
+       * @name clear
+       * @description
+       * handler function which will clear stack
+       * @returns {Void}
+       */
+  clear() {
+    this.top = 0;
+    this.dataStore = []
+  }
+}
+
+module.exports = Stack

test/dataStructures/Queue.test.js

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+const Queue = require('../../src/dataStructures/Queue');
+
+describe('Queue data structure', () => {
+
+  it ('Should have empty Queue when instantiated', () => {
+    const queue = new Queue();
+    expect(queue.dataStore.length).toBe(0);
+  });
+
+  it('Should add the item in last in queue', () => {
+    const queue = new Queue();
+    queue.enqueue(1);
+    queue.enqueue(2);
+    expect(queue.back()).toBe(2);
+  });
+
+
+  it('Should remove items from the front in the Queue', () => {
+    const queue = new Queue();
+    queue.enqueue(1)
+    queue.enqueue(2)
+    queue.enqueue(3)
+    expect(queue.dequeue()).toBe(1);
+    expect(queue.dequeue()).toBe(2);
+    expect(queue.dequeue()).toBe(3);
+  });
+
+  it('Should print a correct representation of the queue as string', () => {
+    const queue = new Queue();
+    queue.enqueue(1);
+    queue.enqueue(2);
+    queue.enqueue(3);
+    expect(queue.dataStore.toString()).toBe('1,2,3');
+  });
+
+  it('Should peek front element from queue', () => {
+    const queue = new Queue();
+    queue.enqueue(1);
+    queue.enqueue(2);
+    queue.enqueue(3);
+    expect(queue.front()).toBe(1);
+  });
+  it('Should peek back element from queue', () => {
+    const queue = new Queue();
+    queue.enqueue(1);
+    queue.enqueue(2);
+    queue.enqueue(3);
+    expect(queue.back()).toBe(3);
+  });
+  it('Should empty queue', () => {
+    const queue = new Queue();
+    queue.enqueue(1);
+    queue.enqueue(2);
+    queue.enqueue(3);
+    expect(queue.empty().length).toBe(0);
+  });
+})

test/dataStructures/Stack.test.js

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+const Stack = require('../../src/dataStructures/Stack');
+
+describe('Stack data structure', () => {
+
+  it ('Should have empty stack when instantiated', () => {
+    const stack = new Stack();
+    expect(stack.top).toBe(0);
+    expect(stack.dataStore.length).toBe(0);
+  });
+
+  it('Should add the first item on top', () => {
+    const stack = new Stack();
+    stack.push(1);
+    expect(stack.dataStore.toString()).toBe('1');
+  });
+
+
+  it('Should remove items from the top of the stack', () => {
+    const stack = new Stack();
+    stack.push(1)
+    stack.push(2)
+    stack.push(3)
+    expect(stack.pop()).toBe(3);
+    expect(stack.pop()).toBe(2);
+    expect(stack.pop()).toBe(1);
+  });
+
+  it('Should print a correct representation of the stack as string', () => {
+    const stack = new Stack();
+    stack.push(1);
+    stack.push(2);
+    stack.push(3);
+    expect(stack.dataStore.toString()).toBe('1,2,3');
+  });
+
+  it('Should peek top element from stack', () => {
+    const stack = new Stack();
+    stack.push(1);
+    stack.push(2);
+    stack.push(3);
+    expect(stack.peek()).toBe(3);
+  });
+})