A simple way of automatically render Add and Delete buttons to collections through form theming. You just need to implement the "addPrototype(form_id)" Javascript function. #Symfony2 #Form #Collection

fields.html.twig

{% extends "form_div_layout.html.twig" %}

{% block form_row %}
{% spaceless %}
    <div>

        {{ form_label(form) }}
        {{ form_errors(form) }}
        {{ form_widget(form) }}

        {% if form.parent.vars.allow_delete|default(false) %}
        <button type="button" onclick="this.parentElement.parentElement.removeChild(this.parentElement)">
            &times;
        </button>
        {% endif %}
    </div>
{% endspaceless %}
{% endblock form_row %}

{% block collection_widget %}
{% spaceless %}

    {{ parent() }}

    {% if allow_add|default(false) %}
        <button type="button" onclick="addPrototype('{{ id }}')">
            &plus;
        </button>
    {% endif %}

{% endspaceless %}
{% endblock collection_widget %}