Shopify: Filter by Vendor

filter-vendor.liquid

<!-- add the vendor as product tag to product then use this code in collection.liquid -->
<!-- if we are on a collection page that is either custom or smart -->
{% if collection.url != blank %}
<h4>Shop by vendor:</h4>
<ul>
	{% for product_vendor in collection.all_vendors %}
	<li>
		{% if current_tags contains product_vendor %}
		<a class="active" href="{{ collection.url }}">{{ product_vendor }}</a>
		{% else %}
		<a href="{{ collection.url }}/{{ product_vendor | handle }}">{{ product_vendor }}</a>
		{% endif %}
	</li>
	{% endfor %}
</ul>
{% endif %}