How to write if/then/elseif/else in Drupal 8 Twig templates

As a quick note Drupal programming note, here’s an example of how to write if/then/elseif/else in Drupal 8 Twig templates:

{% if node.getType == 'photo' %}
...
{% elseif node.getType in ['book', 'page'] %}
...
{% else %}
...
{% endif %}

While I’m in the neighborhood, here are a few more if conditions I’ve written recently:

{% if node.getType == 'photo' %} 
{% if node.getType not in ['text', 'misc' ] %}
{% if not page %}
{% if page %}

Here are a few if clauses I used with Drupal node URIs:

{{ $uri = path('entity.node.canonical', {'node': node.id}) }}
{% if '/services/' in url %}
{% if uri starts with '/hismb' %}

In summary, I just wanted to show the syntax of how to write the if/elseif/else/endif code with Drupal 8 Twig templates, and I hope that example is helpful.