singlelinkedlist.js

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

class SingleLinkedList {


    constructor() {
        this.head = null;
        this.length = 0;
    }


    addToHead(data) {
        let newNode = new node(data);
        if (this.head == null) {
            this.head = newNode;

        } else {
            newNode.next = this.head;
            this.head = newNode;
        }
        this.length++;
    }


    addToLast(data) {
        let newNode = new node(data);
        if (this.head == null) {
            this.head = newNode;
        } else {
            let currentNode = this.head;
            while (currentNode.next != null) {
                currentNode = currentNode.next;
            }
            currentNode.next = newNode;
        }
        this.length++;
    }


    insertAfter(key, data) {
        if (this.head == null) {
            console.log("The list is empty");
        } else {
            let currentNode = this.head;
            let newNode = new node(data);
            while (currentNode != null) {
                if (currentNode.data == key) {
                    newNode.next = currentNode.next;
                    currentNode.next = newNode;
                    break;
                }
                currentNode = currentNode.next;
            }
        }
        this.length++;
    }

    search(value) {
        if (this.head == null) {
            console.log("The list is empty");
            return false;
        } else {
            let currentNode = this.head;
            while (currentNode != null) {
                if (currentNode.data == value) {
                    console.log(`${value} is found in the list`);
                    return true;
                }
                currentNode = currentNode.next;
            }
        }
        console.log(`${value} is not in the list`);
        return false;
    }



    delete(value) {
        if (this.head == null) {
            console.log("The list is empty");
        } else {
            let currentNode = this.head;
            let previousNode = null;
            while (currentNode != null) {
                if (currentNode.data == value) {
                    break;
                }
                previousNode = currentNode;
                currentNode = currentNode.next;
            }

            if (currentNode == null) {
                console.log(`${value} is not in the list`);
            } else {
                if (currentNode.data == this.head.data) {
                    this.head = currentNode.next;
                    this.length--;
                } else {
                    previousNode.next = currentNode.next;
                    this.length--;
                }
                console.log(`${value} is deleted from  the list`);
            }
        }
    }


    getSize() {
        console.log(this.length);
    }

    display() {
        if (this.head == null) {
            console.log('List is empty');
        } else {
            let currentNode = this.head;
            while (currentNode != null) {
                console.log(currentNode.data);
                currentNode = currentNode.next;
            }
        }
    }
}

/* Example
var sl = new SingleLinkedList();
sl.addToHead(1);
sl.addToHead(2);
sl.addToHead(3);
sl.addToHead(4);
sl.addToHead(5);
sl.addToLast(6)
sl.insertAfter(6,7)
sl.delete(7);
sl.search(6);
sl.search(7);
sl.display();
*/