{# Sets a default value if not defined #}
{% set query = query ?? '' %}

<div class="field">
    {# Replaces only the `#results` div #}
    <input sprig s-trigger="keyup changed" s-replace="#results" type="text" name="query" value="{{ query }}" placeholder="Search" class="text">
</div>

<div id="results">
    {% if query %}
        {% set entries = craft.entries.search(query).all() %}
        {% if entries|length %}
            {% for entry in entries %}
                <h2>{{ entry.title }}</h2>
            {% endfor %}
        {% else %}
                No results
        {% endif %}
    {% endif %}
</div>