singlyLinkedList.js

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

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

    push(val){
        var newNode = new Node(val);
        if(!this.head){
            this.head = newNode;
            this.tail = this.head;
            this.length++;
        }else{
            this.tail.next = newNode;
            this.tail = newNode;
            this.length++; 
        }
        return this;
    }

    pop(){
        if(!this.head) return undefined;
        var current = this.head;
        var newTail = current;
        while(current.next){
            newTail = current;
            current= current.next;
        }
        this.tail= newTail;
        this.tail.next = null;
        this.length--;
        if(this.length===0){
            this.head = null;
            this.tail = null;
        }
        return current;
    }

    shift(){
        if(!this.head) return undefined;
        var currentHead = this.head;
        this.head = currentHead.next;
        this.length--;
        if(this.length===0){
            this.tail = null;
        }
        return currentHead;
    }
    unshift(val){
        var newNode = new Node(val);
        if(!this.head){
            this.head = newNode;
            this.tail = this.head;
            this.length++;
        }else{
            newNode.next=this.head;
            this.head = newNode;
            this.length++;
        }
        return this;
    }
    get(index){
        if(index <0 || index >= this.length) return undefined;
        var current = this.head;
        var counter = 0;
        while(counter!==index){
            current = current.next;
            counter++;
        }
        return current;
    }
    set(index , val){
        var foundNode = this.get(index);
        if(foundNode){
            foundNode.val = val;
            return true;
        }
        return false;
    }
    insert(index, val){
        if(index<0 || index > this.length) return false;
        if(index===this.length) return !!this.push(val);
        if(index===0) return !!this.unshift(val);
        var newNode = new Node(val);
        var prev = this.get(index-1);
        var temp = prev.next;
        prev.next = newNode;
        newNode.next = temp;
        this.length++;
        return true;
    }
    remove(index){
        if(index < 0 || index>=this.length) return false;
        if(index===this.length-1) return this.pop();
        if(index===0) return this.shift();
        var prev = this.get(index-1);
        var removed = prev.next;
        prev.next = removed.next;
        this.length--;
        return removed;
    }
    reverse(){
        var node = this.head;
        this.head = this.tail;
        this.tail= node;
        var next;
        var prev = null;
        for(var i = 0; i<this.length; i++){
            next = node.next;
            node.next = prev;
            prev = node;
            node = next;
        }
        return this;
    }
    print(){
        var arr = [];
        var current = this.head;
        while(current){
            arr.push(current.val);
            current = current.next;
        }
        console.log(arr);
    }
}