Jekyll Block Tag with custom context

Give an array in Jekyll’s _data structure:

_data/array.yml

- id: id1
  name: name1
- id: id2
  name: name2

How can I create a block tag that will lookup the object with the specific id and pass in as context inside the block tag. Like this

{% item id1 %}
 <p>{{ site.data.array.length }}</p>
 <p>{{ item.name }}</p>
{% enditem %}

I’ve made this so far:

module Jekyll
  class ItemBlock < Liquid::Block
    def initialize(tag_name, markup, tokens)
      super
      @tag = markup
    end

    def render(context)

      jekyllSite = context.registers[:site]

      items = jekyllSite.data['array'].select { |item|
        item['id'] == context[@tag.strip]
      }

      context.environments.first['item'] = items.first

      super
    end
  end
end

Liquid::Template.register_tag("item", Jekyll::ItemBlock)

But now the item is available to the whole template even outside the block.

{% item id1 %}
 <p>{{ site.data.array.length }}</p>
 <p>{{ item.name }}</p>
{% enditem %}

<p>{{ item.name }}</p>

Is this the correct approach?

I can’t answer your question but have you looked at using an include and passing in a parameter instead of making a plugin?

What I want is to delegate the searching through the items list to a Ruby plugin, instead of doing it in Liquid. That’s why I don’t want to do it using include.