Single Linked List in Javascript.js

class SingleLinkedList{

	constructor(){
		this.firstNode = null;
	}

	//Insert item at beginning of list
	insert(data){
		var newNode = new Node(data);
		newNode.nextNode = this.firstNode;
		this.firstNode = newNode;	
	}
	
	//get Item at index
	itemAtIndex(index){
		var currentIndex = 0;
		var currentNode = this.firstNode;
		while(currentIndex !== index){
			currentIndex++;
			if(currentNode.nextNode === null)
				return null;
			else
				currentNode = currentNode.nextNode;
		}
		return currentNode.data;
	}
	
	//delete item at index
	delete(index){
	
		if(index === 0){
			this.deleteFirst();
			return null;
		}
		
		var currentIndex = 0;
		var nodeBefore;
		var currentNode = this.firstNode;
		while(currentIndex !== index){
			currentIndex++;
			if(currentNode.nextNode === null)
				return;
			
			nodeBefore = currentNode;
			currentNode = currentNode.nextNode;
			
		}
		
		nodeBefore.nextNode = currentNode.nextNode;
	}
	
	deleteFirst(){
		this.firstNode = this.firstNode.nextNode;
	}
	
}


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

}


//TEST
var list = new SingleLinkedList();
list.insert("hello");
list.insert("how are you");
console.log(list.delete(1));
console.log(list);