shopify-remove-duplicate-canonical-url.liquid

<!-- template.name {{ template.name }} -->     
{% case template.name %}
  {% when 'index' %}
    <link rel="canonical" href="{{ shop.url }}">      
  {% when 'collection' %} 
    <link rel="canonical" href="{{ shop.url }}/collections/{{ collection.handle }}">   
  {% when 'product' %}   
    <link rel="canonical" href="{{ shop.url }}/products/{{ product.handle }}">       
  {% when 'page' %}
    <link rel="canonical" href="{{ shop.url }}/pages/{{ page.handle }}">                
  {% else %}
    <link rel="canonical" href="{{ canonical_url }}">
{% endcase %} 
{% endif %}