Singly Linked List

A linked list is a linear collection of data elements, each element points to the next.
Singly linked lists contain nodes which have a data field as well as next field, which points to the next node in line of nodes.
Operations that can be performed on singly linked lists include insertion, deletion and traversal.

A singly linked list whose nodes contain two fields: an integer value and a link to the next node

The next field of last node is set to null

Operations

Creation

A linked list can be created by just creating a new object using the LinkedList constructor.

// Constructor function for creating the Linked list 
function LinkedList() {
    this.start = null;
    // it also contains the reference to the starting node
}

// Constructor function for creating the Nodes 
function Node(data) {
    this.data = data;
    this.next = null;   // reference to the next node
}

creating a new Linked List

var list = new LinkedList();
// populating  the list with random values
for (var i = 0; i < 7; i++) {
    list.add(Math.floor(Math.random() * 100));
}
console.log(list);

Traversing

Once the linked list has been created, its nodes can be retrieved by just processing the starting node, then referening to the next node and repeating the process recursively.

LinkedList.prototype.traverse = function () {
    this.start.visit()
}

Node.prototype.visit = function () {
    if (this != null) {
        console.log(this.data);
        if (this.next != null) {
            this.next.visit();
        }
    }
}

Insertion of new node

If the first node is null then it becomes the starting node.

LinkedList.prototype.add = function (value) {
    var n = new Node(value);
    if (this.start == null) {
        this.start = n;
    } else {
        this.start.addNode(n);
    }
}

Or else it will be one of the following next node of the start.

Node.prototype.addNode = function (n) {
    if (this.next == null) {
        this.next = n;
    } else {
        this.next.addNode(n);
    }
};

Deletion

In case of deletion two situations arise which are

1. If the node to be deleted is the start node or the fisrt node

   LinkedList.prototype.delete = function (value) {
    if (this.start.data == value) {
        var tempNode = this.start;
        this.start = tempNode.next;
        }
    }

2. If the node to be deleted is in between somewhere

LinkedList.prototype.delete = function (value) {
     if (this.start.data == value) {
         var tempNode = this.start;
         this.start = tempNode.next;
     } else {
         this.start.delete(value);
     }
 }
 Node.prototype.delete = function (value) {
     var tempNode = this.next;
     if (tempNode.data == value) {
         this.next = tempNode.next;
         console.log('Node deleted');
     } else {
         this.next.delete(value);
     }
 }
![List](https://github.com/ilavisharma/singlyLinkedList/blob/master/assets/images/list_delete.PNG)