Linked Lists

gistfile1.txt

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

class LinkedList{
    constructor(){
        this.head = null;
    }
    
    insertFirst(record){
        this.head = new Node(record, this.head); 
        // console.log(this.head.next);
    }
    
    size(){
        let counter = 0;
        let node = this.head;
        while (node) {
               counter++
            node = node.next;
               }
        return counter; 
    }
    
    getLast(){
        let node = this.head; 
        while (node) {
            if (!node.next){
                return node; 
                }
            
            node = node.next; 
                   
               }
        return node; 
    }
    
    clear(){
        this.head = null; 
    }
    
    removeFirst(){
        if (!this.head){
                return null; 
            }
        if (!this.head.next){
            return null; 
        }
        
        return this.head = this.head.next;
    }
    removeLast(){
        if (!this.head){
                return null; 
        }
        if (!this.head.next){
           return this.head = null;
        }
        let node = this.head;
        let prev; 
        while (node.next) {
            prev = node; 
            node = node.next; 
        }
        prev.next = null;
        return this.head; 
    }
    
    
    
}