How to use the hasNext() and hasPrevious() method for the `smart-list` Linked List module for Node

Question

I am using singly-linked-list to manage my in-out transactions but singly-linked-list is not provided hasPrevious() method.

Why I need hasPrevious() method ?

In some conditions I want to iterate linked list twice in same method signature check here

So I moved to smart-list which is provided hasPrevious() but I could not make this work. See example

Can anyone please suggest me how to use hasNext() and hasPrevious() in smart-list or any other solution?

Could you share what you've attempted so far? It's a little difficult to provide help without some code. — gnerkus, Mar 19 '16 at 07:08

score 0 · Answer 1 · answered Mar 19 '16 at 07:56

0

From the source of the list for the smart-list module, the iterators are present in the _first and _last properties of the list:

var List = require("smart-list")
var templist = new List()

templist.push("foo");

templist._first.hasNext(); // false

answered Mar 19 '16 at 07:56

gnerkus

Thank you for your response but how to get value "foo" in variable – Priyanka Pawar Mar 19 '16 at 08:15
The `data` property contains the value. So `console.log(a.data);`. – gnerkus Mar 19 '16 at 08:22
[see this example](https://tonicdev.com/56ebff0884ccdd11001ebed0/56eced7384ccdd11001eeefd) what if I want to take sum of all elements present in linked list – Priyanka Pawar Mar 19 '16 at 08:29
`templist._first` contains the first element ('101'). – gnerkus Mar 19 '16 at 08:32
Yes I got it but how can I traverse through list till nth record. It only traverse up to number of times I have written next() – Priyanka Pawar Mar 19 '16 at 08:38

1 Answers1