Replace function inside value not working - replace

Question

Maybe I'm doing it wrong (tried several ways to achieve my goal) or overlooking something here.
What I'd like to achieve is this:
When I use the Live-search function, I get categories containing the search keyword (like: Paint -> Paint buckets, Paint brushes, Paint colors etc.) which works like a charm. The one thing I need is to style the searched keyword in the presented categories like:
Paint bucket,
Paint brushes,
Color paint
This is the code I have at the moment:
{% if (products.length + categories.length + pages.length) == 0 %}
<div id="Pi56dYpB" class="undefined"> No results for:
<b>{{ query }}</b>...
</div>
{% endif %}
{% if categories.length > 0 %}
<div class="categories">
{% for category in categories %}
{% if loop.index < 7 %}
<a class="p-0" href="{{ category.url }}" style="all:inherit;">
<h3 id="bvwiyjEN" class="undefined">{{ category.name|replace({{ query }}: "<strong>"{{ query }}"<strong>"})|raw }}</h3>
</a>
{% endif %}
{% endfor %}
{% endif %}
Unfortunately this isn't working. I did check if the {{ query }} value is accessible with this simple line of code:
<h3 id="bvwiyjEN" class="undefined">{{ category.name }} - {{ query }}</h3>
No problems found here.
Did I use the wrong syntax in my code maybe? Any help would be appreciated!

Answer 1

replace({{ query }}) is the wrong syntax - replace(query) should work, as you don't want to echo the variable query here

Answer 2

As Nico Haase pointed out already, {{ ... }} is used to output variables, this translate to something like <?php echo $foo; ?> and can't/shouldn't be used inside statements
Furthermore, the filter replace expects an array of keys to replace with the values.
You would need to change your code to the following:
{% for category in categories %}
{{ category|replace({ (query): '<strong>'~query~'</strong>',})|raw }}
{% endfor %}
demo
Some notes:
The filter replace uses the PHP function strtr in the background. This mean the output will be case-sensitive. If you don't want this, I'd advice you to follow through here
Wrapping the key with parantheses is mandatory. This will force twig to evaluate/interpolate the value of the key - demo