In a Twig .htm partial
<div class="sidebar-widget">
{% component "postBlock" score=55 name="Johan" %}
<div class="nonsense meta">
{% partial 'nonsense' score=75 name="Marga" %}
</div>
</div>In the nonsense twig that is a child of the previous .htm partial
<div class="sidebar-element">
<div>My name is: {{ name|default('John Doe') }}</div>
<div>My score is: {{ score|default('No score') }}</div>
</div>In the component postBlock, onRender function
function onRender() {
$score = $this->property('score'); // 55
$name = $this->property('name'); // Johan
}To pass from a parent twig to a child twig, you don't have to use the onRender function in the component, only if you want to modify things and pass is from there to the twig.