{% set value = form.state[item.name] %}
{% set error = form.errors[item.name] %}
{% set classes = 'form-check-input' %}
{% if error %}
  {% set classes = classes ~ ' is-invalid' %}
{% endif %}
{% set required = item.isRequired ? ' required' : '' %}
{% set disabled = item.isDisabled ? ' disabled' : '' %}
{% set extra = item.extra ? item.extra : '' %}
{% set extra = extra ~ (value == 'on' ? ' checked' : '') %}
<div class="mb-3 form-check">
  <input type="checkbox" class="{{ classes }}" id="form-{{ item.name }}" name="{{ item.name }}"{% if value %} value="{{ value }}"{% endif %}{{ required }}{{ disabled }} {{ extra }}>

  {% if item.label %}
    <label for="form-{{ item.name }}" class="form-check-label">{{ item.label }}</label>
  {% endif %}

  {% if error %}
    <div class="invalid-feedback">{{ error }}</div>
  {% endif %}
</div>