freeCodeCamp/curriculum/challenges/arabic/08-coding-interview-prep/data-structures/create-a-doubly-linked-list.arabic.md

id, title, challengeType, videoUrl, localeTitle

id	title	challengeType	videoUrl	localeTitle
587d825a367417b2b2512c87	Create a Doubly Linked List	1

Description

undefined

Instructions

undefined

Tests

tests:
  - text: ''
    testString: 'assert((function() { var test = false; if (typeof DoublyLinkedList !== "undefined") { test = new DoublyLinkedList() }; return (typeof test == "object")})(), "The DoublyLinkedList data structure exists.");'
  - text: ''
    testString: 'assert((function() { var test = false; if (typeof DoublyLinkedList !== "undefined") { test = new DoublyLinkedList() }; if (test.add == undefined) { return false; }; return (typeof test.add == "function")})(), "The DoublyLinkedList has a method called add.");'
  - text: ''
    testString: 'assert((function() { var test = false; if (typeof DoublyLinkedList !== "undefined") { test = new DoublyLinkedList() }; if (test.remove == undefined) { return false; }; return (typeof test.remove == "function")})(), "The DoublyLinkedList has a method called remove.");'
  - text: ''
    testString: 'assert((function() { var test = false; if (typeof DoublyLinkedList !== "undefined") { test = new DoublyLinkedList() }; return (test.remove(100) == null); })(), "Removing an item from an empty list returns null.");'
  - text: ''
    testString: 'assert((function() { var test = false; if (typeof DoublyLinkedList !== "undefined") { test = new DoublyLinkedList() }; test.add(5); test.add(6); test.add(723); return (test.print().join("") == "56723"); })(), "The add method adds items to the list.");'
  - text: ''
    testString: 'assert((function() { var test = false; if (typeof DoublyLinkedList !== "undefined") { test = new DoublyLinkedList() }; test.add(50); test.add(68); test.add(73); return (test.printReverse().join("") == "736850"); })(), "Each node keeps track of the previous node.");'
  - text: ''
    testString: 'assert((function() { var test = false; if (typeof DoublyLinkedList !== "undefined") { test = new DoublyLinkedList() }; test.add(25); test.add(35); test.add(60); test.remove(25); return ( test.print().join("") == "3560" ) })(), "The first item can be removed from the list.");'
  - text: ''
    testString: 'assert((function() { var test = false; if (typeof DoublyLinkedList !== "undefined") { test = new DoublyLinkedList() }; test.add(25); test.add(35); test.add(60); test.remove(60); return ( test.print().join("") == "2535" ) })(), "The last item can be removed from the list.");'

Challenge Seed

var Node = function(data, prev) {
  this.data = data;
  this.prev = prev;
  this.next = null;
};
var DoublyLinkedList = function() {
  this.head = null;
  this.tail = null;
  // change code below this line
  // change code above this line
};

After Test

console.info('after the test');

Solution

// solution required