Linked List Overview

Data structures of this type consist of a series of nodes, each with a value and a reference to the node following it.

Advantages of Linked Lists

Disadvantages of Linked Lists

In Javascript, Linked Lists will look like this.

const linkedlist = {
  head: {
      value: 1
      next: {
          value: 2                                            
          next: {
              value: 3
              next: {
                  value: 4
                  next: null	
                  }
              }
          }
      }
  }
} 

There are 3 types of Linked Lists

Singly Linked Lists

Each node only has one pointer to the node after it.

Implementation of ListNode

class ListNode {
  constructor(data) {
      this.data = data
      this.next = null                
  }
}

Following that is a linked list class that keeps the lists head pointer.

class LinkedList {
  constructor(head = null) {
      this.head = head
  }
}

Construct a LinkedList class instance

let list = new LinkedList();

Lets pass value to node and print log

class Node {
  constructor(val) {
      this.data = val;
      this.next = null;
  }
}

var node1 = new Node(1);

console.log(node1) // Node { data: 1, next: null }

Lets pass multiple value to node and print logs

class Node {
  constructor(val) {
      this.data = val;
      this.next = null;
  }
}

let head;
  
// Inserts a new Node 
function add(new_data) {
      
let add_node = new Node(new_data);
  
// Make next Node as head
add_node.next = head;
  
// Point to new Node
head = add_node;
}
    
add(1);
add(2);
add(3);

/* In JavaScript, a node will look like this
Node{
  data: 3,
  next: Node{
    data: 2,
    next: Node{
      data: 1,
      next: undefined
    }
  }
}
*/ 

Lets find length of the nodes now

class Node {
constructor(val) {
    this.data = val;
    this.next = null;
 }
}

let head;
  
// Inserts a new Node 
function add(new_data) {
      
  let add_node = new Node(new_data);
    
  // Make next Node as head
  add_node.next = head;
    
  // Point to new Node
  head = add_node;
}
    
add(1);
add(2);
add(3);

function getLength() {
  let count = 0;
  let temp = head;
      
  while (temp != null) {
      count++;
      temp = temp.next;
  }
return count;
}
    
console.log('Length is :', getLength()) // Length is : 3