node-structures

node-structures

Basic Data Structures for use in JavaScript (server-side, client side)

Description

The Library provides the following Data Structure Implementations

• Stack
• Queue
• Priority Queue
• Linked List

Installation

Server-side: npm install node-structures

Client-side: bower install node-structures

Usage

###Stack

   const Stack = require('node-structures').Stack;
   let stack = new Stack();
  
   /**
    * Tests if this stack is empty.
    * @returns {boolean} - true if and only if this stack contains no items; false otherwise.
    */
   stack.isEmpty();
  
   /**
    * Pushes an item onto the top of this stack.
    * @param item - the item to be pushed onto this stack.
    * @return {boolean} - true if the item is pushed.
    */
   stack.push(3);
  
   /**
    * Looks at the object at the top of this stack without removing it from the stack.
    * @throws {Error} - if this stack is empty.
    * @returns {*} - the object at the top of this stack (the last item of the Vector object).
    */
   stack.peek();
  
   /**
    * Removes the object at the top of this stack and returns that object as the value of this function.
    * @throws {Error} - if this stack is empty.
    * @return {*} - the object at the top of this stack (the last item of the Vector object).
    */
   stack.pop();
  
   /**
    * Returns the size of the stack.
    * @returns {Number} - the size of the stack.
    */
   stack.size();

###Queue

   const Queue = require('node-structures').Queue;
   let queue = new Queue();
  
   /**
    * Returns the size of the queue.
    * @returns {Number} - the size of the queue.
    */
   queue.size();
   
  /**
   * Tests if this queue is empty.
   * @returns {boolean} - true if and only if this queue contains no items; false otherwise.
   */
  queue.isEmpty();
  
  /**
   * Inserts the specified element into this queue.
   * @param element - the element to add
   * @return {boolean} Returns true
   */
  queue.add(3);
  
  /**
   * Retrieves and removes the head of this queue. This method differs from poll only in that it throws an exception
   *  if this queue is empty.
   * @throws {Error} when the queue is empty.
   * @return {*} Returns the head of this queue
   */
  queue.remove();
  
  /**
   * Retrieves and removes the head of this queue, or returns null if this queue is empty.
   * @returns {*} Returns the head of this queue, or null if this queue is empty.
   */
  queue.poll();
  
  /**
   * Retrieves, but does not remove, the head of this queue, or returns null if this queue is empty.
   * @returns {*} Returns the head of this queue, or null if this queue is empty.
   */
  queue.peek();

###Priority Queue

  const PriorityQueue = require('node-structures').PriorityQueue;
  /**
   * Creates an empty PriorityQueue with default comparator.
   * 
   * Default Comparator: Compares `a` and `b`, when `a > b` it returns a positive number, when `a` = `b` it returns 0,
   *  and when `a < b` it returns a negative number.
   */
  let priorityQueue = new PriorityQueue();
  
  /**
   * Creates an empty PriorityQueue with custom comparator.
   *
   * (`a > b` - return a positive number, when `a` = `b` return 0, and when `a < b`) return a negative number.
   */
  const comparator = function(a, b){
     return a - b; // define your own one.
  };
  let priorityQueue = new PriorityQueue(comparator);
  
  /**
   * Returns the number of elements in this collection
   *
   * @returns {Number} - the number of elements in this collection
   */
   priorityQueue.size();
   
  /**
   * Tests if this priority queue is empty.
   *
   * @returns {boolean} - true if and only if this priority queue contains no items; false otherwise.
   */
   priorityQueue.isEmpty();
   
   /**
    * Inserts the specified element into this priority queue.
    *
    * @param element - the element to add
    * @returns {boolean} Returns true
    */
    priorityQueue.add(40);
    
    /**
     * Retrieves and removes the head of this priority queue, or returns null if this priority queue is empty.
     *
     * @returns {*} Returns the head of this priority queue, or null if this priority queue is empty.
     */
     priorityQueue.poll();
     
     /**
      * Retrieves, but does not remove, the head of this priority queue, or returns null if this priority queue is empty.
      *
      * @returns {*} Returns the head of this priority queue, or null if this priority queue is empty.
      */
      priorityQueue.peek();

###LinkedList

  const LinkedList = require('node-structures').LinkedList;
  let linkedList = new LinkedList();
  
  /**
   * Tests if this LinkedList is empty.
   * @returns {boolean} - true if and only if this LinkedList contains no items; false otherwise.
   */
  linkedList.isEmpty();
  
  /**
   * Inserts the specified element at the beginning of this list.
   * @param data - the element to add
   */  
  linkedList.addFirst("A");
  
  /**
   * Appends the specified element to the end of this list.
   * @param data - the element to add
   */
  linkedList.addLast("B");
  
  /**
   * Inserts the specified element at the specified position in this list.
   * Shifts the element currently at that position (if any) and any subsequent elements to the right
   * (adds one to their indices).
   * @throws IndexOutOfBoundsException - if the index is out of range (index < 0 || index >= size())
   * @param index - index at which the specified element is to be inserted
   * @param element - element to be inserted
   */
  linkedList.add(1, "C");
  
  /**
   * Removes the element at the specified position in this list. Shifts any subsequent elements to the left
   * (subtracts one from their indices).
   * Returns the element that was removed from the list.
   * @throws IndexOutOfBoundsException - if the index is out of range (index < 0 || index >= size())
   * @param index - the index of the element to be removed
   * @returns {*} - the element previously at the specified position
   */
  linkedList.remove(2);
  
  /**
   * Returns the element at the specified position in this list.
   * @throws IndexOutOfBoundsException - if the index is out of range (index < 0 || index >= size())
   * @param index - index of the element to return
   * @returns {*} - the element at the specified position in this list
   */
  linkedList.get(1);
  
  /**
   * Returns the number of elements in this list.
   * @returns {Number} - the number of elements in this list.
   */
  linkedList.size();
   
  /**
   * Removes all of the elements from this list. The list will be empty after this call returns.
   */
  linkedList.clear();

License

MIT