shopify - Previous / Next button for a linklist - not working as expected -

i'm attempting build "next / previous" page navigation system pages in linklist.

the code below works expected... except on first , last page on linklist. want "previous" button not show on first page, , "next" button not show on last page.

on first page, "previous" button shows, , points last page.

on last page, "next" button shows, points nowhere.

where going wrong? thing can think i'm not giving variables correct types (i'm relatively new liquid).

  {% comment %}     linklist being passed, , size of linklist.   {% endcomment %}    {% assign thislinklist = __page-navigation-arrows %}   {% assign thislinklistsize = linklists[thislinklist].links | plus: 0 %}    {% comment %}     finds index of current page in linklist array, , saves compare find previous , next pages.   {% endcomment %}    {% link in linklists[thislinklist].links %}     {% if page.handle == link.handle %}       {% assign thisindex = forloop.index0 | plus: 0 %}     {% endif %}   {% endfor %}    {% comment %}     saves details of current page, , indexes of previous , nex pages.   {% endcomment %}    {% assign thisname = page.title %}   {% assign thislink = page.url %}    {% assign thisindex = thisindex | plus: 0 %}   {% assign previndex = thisindex | minus: 1 %}   {% assign nextindex = thisindex | plus: 1 %}    {% comment %}     if it's not last page in linklist, save details of next page. if not, assign blank string (used later hide button).   {% endcomment %}    {% if previndex | plus: 0 > 0 %}     {% assign prevname = linklists[thislinklist].links[previndex].title %}     {% assign prevlink = linklists[thislinklist].links[previndex].url %}   {% else %}     {% assign prevname = '' %}     {% assign prevlink = '' %}   {% endif %}    {% comment %}     if it's not first page in linklist, save details of previous page. if not, assign blank string (used later hide button).   {% endcomment %}    {% if nextindex | plus: 0 < thislinklistsize | minus: 1 %}     {% assign nextname = linklists[thislinklist].links[nextindex].title %}     {% assign nextlink = linklists[thislinklist].links[nextindex].url %}   {% else %}     {% assign nextname = '' %}     {% assign nextlink = '' %}   {% endif %}     {% comment %}     display navigation.   {% endcomment %}    <div class="page-navigation-arrows">      {% comment %} hide "previous" if it's first page {% endcomment %}     {% if prevlink != '' or blank %}       <a class="page-navigation-arrows__prev page-navigation-arrows__arrow" href="{{ prevlink }}" title="{{ prevname }}">         <img src="{{ 'page-navigation-prev.svg' | asset_url }}" alt="previous page">       </a>     {% endif %}      {% comment %} hide "next" if it's last page {% endcomment %}     {% if nextlink != '' or blank %}       <a class="page-navigation-arrows__next page-navigation-arrows__arrow" href="{{ nextlink }}" title="{{ nextname }}">         <img src="{{ 'page-navigation-next.svg' | asset_url }}" alt="next page">       </a>     {% endif %}    </div> 

no time test this, believe code works.

but there few things:

{% if nextlink != '' or blank %}

this not valid if condition. should be:

{% if nextlink != '' or nextlink == blank %}

---

this not valid if statement well:

{% if previndex | plus: 0 > 0 %}

it returns true. should become:

{% assign previndex = previndex | plus: 0 %} {% if previndex > 0 %}     ... {% endif %} 

once fix these issues should working properly.