Symfony - Render bootstrap 4 input-group (append)

form_layout.html.twig

{% use "bootstrap_4_layout.html.twig" %}

{# Override form_widget_simple block to render bootstrap input-group with prepend and append #}
{% block form_widget_simple -%}
	{%- if input_prepend is defined or input_append is defined -%}
		<div class="input-group">
	{%- endif -%}
	{%- if input_prepend is defined -%}
		<div class="input-group-prepend">
			<span class="input-group-text" id="{{ form.vars.id ~ "_prepend" }}">{{ input_prepend | raw }}</span>
		</div>
	{%- endif -%}
	{{- parent() -}}
	{%- if input_append is defined -%}
		<div class="input-group-append">
			<span class="input-group-text" id="{{ form.vars.id ~ "_append" }}">{{ input_append | raw }}</span>
		</div>
	{%- endif -%}
	{%- if input_prepend is defined or input_append is defined -%}
		</div>
	{%- endif -%}
{%- endblock form_widget_simple %}

{# Example of using an input-group with «m²» addon for a specific form field #}
{% block _project_facadeArea_widget -%}
    {% set input_append = 'm²' %}
    {{ block('form_widget_simple') }}
{%- endblock %}

{{ form_row(form.path, {'input_prepend': '/home'}) }}
{{ form_row(form.end, {'input_prepend': 'to', 'input_append': 'm'}) }}