Linked List

linkedList.js

function Node(data) {
	this.data = data;
	this.next = null;
	this.prev = null;
}

function linkedList() {
	this.head = null;
	this.size = 0; 
}

linkedList.prototype.add = function(data) {
	if(!data || Object.prototype.toString.call(data) === '[object Function]') {
		throw('Pass valid data');
	}

	var node = new Node(data);
	var current = this.head;
	var prev = null;

	if (!current) {
		this.head = node;
	} else {
		while(current.next) {
			prev = current;
			current = current.next;
		}

		current.next = node;
		current.prev = prev;
	}
	
	++this.size;

	return this;
};

linkedList.prototype.remove = function(data) {
	var current = this.head;

	if(!current || (current && !current.next)) {
		throw('Can\'t remove head');
	}

	for(var node = current; node && node.next; node = node.next) {
		current = node;

		if(node.next.data === data) {
			node.next = node.next.next;
			this.size--;
		}

		if (node.prev && node.prev.data === data) {
			node.prev = node.prev.prev;
		}
	}

	return this;
};

linkedList.prototype.peak = function() {
	return this.head;
};

linkedList.prototype.size = function() {
	return this.size;
};

linkedList.prototype.isEmpty = function() {
	return this.size === 0;
};

var list = new linkedList;

list.add('text');
list.add('text1');
list.add('text2');
list.add('text3');
list.add('text1');
list.remove('text1');

console.log(list);