TWIG - include variables in different template - twig

Question

I would like to include the same variables in different templates
vars_catchphrase.twig
{% set catchphrase_size = '' %}
{% if var.tile_catchphrase|length <= 4 %}
{% set catchphrase_size = 'size-lg' %}
{% elseif var.tile_catchphrase|length >= 5 and var.tile_catchphrase|length <= 8 %}
{% set catchphrase_size = 'size-md' %}
{% elseif var.tile_catchphrase|length >= 9 and var.tile_catchphrase|length <= 12 %}
{% set catchphrase_size = 'size-sm' %}
{% elseif var.tile_catchphrase|length >= 13 %}
{% set catchphrase_size = 'size-xs' %}
{% endif %}
I tried to include with this (because the context is sometime different) :
{% include 'vars_catchphrase.twig' with { 'var' : post } %}
When the context is different from post I use another one :
{% include 'vars_catchphrase.twig' with { 'var' : item } %}
example.twig
{% for item in list %}
{% include 'vars_catchphrase.twig' with { 'var' : item } %}
<p class="catchphrase {{ catchphrase_size }}">{{ item.title }}</p>
{% endfor %}
The variable is empty. Can I have some help please ?

Answer 1

Templates you include have their own variable scope, this means variables defined inside this template will not be known out the template. This said, included templates also can't alter the parent's context (by default), this is due to twig passing the context array by value, not by reference.
foo.twig
{% set foo = 'foo' %}
{% include 'bar.twig' %}
{{ foo }}
bar.twig
{% set foo = 'bar' %}
The example above will still output foo
In order to solve your problem, I'd suggest adding a custom filter to twig
<?php
$twig->addFilter(new \Twig\TwigFilter('catchphrase_size', function($value) {
switch(true) {
case strlen($value->tile_catchphrase) >= 13: return 'size-xs';
case strlen($value->tile_catchphrase) >= 9: return 'size-sm';
case strlen($value->tile_catchphrase) >= 5: return 'size-md';
default: return 'size-lg';
}
});
This way you can use the filter where ever,
{% for item in list %}
<p class="catchphrase {{ item|catchphrase_size }}">{{ item.title }}</p>
{% endfor %}