Include a part template on specific node page

Question

I would like to include some custom html code only on a specific node. I created "parts" directory and put a custom twig template in it. (mytheme/templates/parts/custom_html.html.twig)

I then copied over the page.html.twig to my templates directory, and included the custom template with:

{% include directory ~ '/templates/parts/custom_html.html.twig' %}

I want to show this only on a certain node, say "node/2". I don't wan't to create a custom template just for this page, like "page--node--2.html.twig".

Is there a way of using a condition to just show this template on the specific node?

Kind of like this?

{% if 'node/2' %}
    {% include directory ~ '/templates/parts/custom_html.html.twig' %}
{% endif %}

Answer 1

If you want override page.html.twig for special node 2. You can try this code

{% if node.id == '2' %}
   {% include directory ~ '/templates/parts/custom_html.html.twig' %}
{% endif %}

if other template you need process in your function theme first:

YOUR_THEME_process_FUNCTION_THEME(&$vars) {
  if ($node = \Drupal::routeMatch()->getParameter('node')) {
    $vars['node'] = $node;
  }
}