How do i display subcategories in octobercms - laravel

Question

I have been on this for a while with octobercms. I don't know if i am going about it the right way. I have my categories and subcategories already set up with nestedtree. In the Category model i used scope below to render just the parent category on a page.
public function scopeCategory($query)
{
return $query->where('parent_id', 0);
It all works fine.i connected it to a record details page by slug which only shows the parent category on the page as a heading.
{% if record %}
<h4>{{ record.cat_title }}</h4>
{% else %}
{{ notFoundMessage }}
{% endif %}
Now i want to render the subcategories here on the details page so when a user clicks on a category in the list page like agriculture the details page shows all the subcategories under agriculture, then the user can navigate further to the products. Not sure how to implement the subcategory part. I have tried a bunch of codes but it does nothing. Any solution to this?
Additional Info: I have already used scope to get only the parent categories on the list page

Answer 1

I am assuming you already used nested-tree [ https://octobercms.com/docs/database/traits#nested-tree ].
First we just pass parent parentCats to our view / page
use HardikSatasiya\SoTest\Models\Categories;
function onStart() {
$this['parentCats'] = Categories::getAllRoot();
}
In page/view to show category and its sub-categories up to N level we can use this render_cats macro
{% import _self as thisPage %}
{% macro render_cats(items) %}
{% import _self as thisPage %}
{% for item in items %}
<li>{{ item.level }} {{ item.title }}
{% if item.childcount > 0 %}
<ul>
{{ thisPage.render_cats(item.children) }}
</ul>
{% endif %}
</li>
{% endfor %}
{% endmacro %}
<ul>
{{ thisPage.render_cats(parentCats) }}
<!-- we are passing parent cats ^ here -->
</ul>
Output
<ul>
<li>
0 Parent Cat 1
<!-- ^ this is level -->
<ul>
<li>
1 Sub cat 1
<ul>
<li>2 Sub Sub cat 1
</li>
<li>2 Sub Sub cat 3
</li>
<li>2 Sub Sub cat 3
</li>
</ul>
</li>
<li>1 Sub cat 2
</li>
</ul>
</li>
<li>
0 Parent Cat 2
<ul>
<li>1 Sub cat 3
</li>
<li>1 Sub cat 4
</li>
</ul>
</li>
</ul>
If any doubt please comment