firefly-iii/resources/views/partials/flashes.twig

<!-- SUCCESS MESSAGE (ALWAYS SINGULAR) -->
{% if Session.has('success') %}
    <div class="alert alert-success alert-dismissible" role="alert">
        <button type="button" class="close" data-dismiss="alert">
            <span aria-hidden="true">&times;</span><span class="sr-only">{{ 'close'|_ }}</span>
        </button>
        <strong>{{ 'flash_success'|_ }}</strong> {{ session('success') }}
    </div>
{% endif %}

<!-- INFO MESSAGE (CAN BE MULTIPLE) -->
{% if Session.has('info') %}
    <div class="alert alert-info alert-dismissible" role="alert">
        <button type="button" class="close" data-dismiss="alert">
            <span aria-hidden="true">&times;</span><span class="sr-only">{{ 'close'|_ }}</span>
        </button>

        <!-- MULTIPLE INFO MESSAGE -->
        {% if session('info') is iterable and session('info')|length > 1 %}
            <strong>
                {{ Lang.choice('firefly.flash_info_multiple', session('info')|length, {count: session('info')|length}) }}:</strong>
            <ul class="list-unstyled">
                {% for inf in session('info') %}
                    <li>{{ inf|raw }}</li>
                {% endfor %}
            </ul>
        {% endif %}
        <!-- SET OF MULTIPLE INFO MESSAGES, BUT THERE IS JUST ONE -->
        {% if session('info') is iterable and session('info')|length == 1 %}
            <strong>{{ 'flash_info'|_ }}:</strong> {{ session('info')[0]|raw }}
        {% endif %}
        <!-- SINGLE INFO MESSAGE -->
        {% if session('info') is not iterable %}
            <strong>{{ 'flash_info'|_ }}:</strong> {{ session('info')|raw }}
        {% endif %}

    </div>

{% endif %}

<!-- WARNING MESSAGE (ALWAYS SINGULAR) -->
{% if Session.has('warning') %}
    <div class="alert alert-warning alert-dismissible" role="alert">
        <button type="button" class="close" data-dismiss="alert">
            <span aria-hidden="true">&times;</span><span class="sr-only">{{ 'close'|_ }}</span>
        </button>
        <strong>{{ 'flash_warning'|_ }}</strong> {{ session('warning') }}
    </div>
{% endif %}

<!-- ERROR MESSAGE (CAN BE MULTIPLE) -->
{% if Session.has('error') %}
    <div class="alert alert-danger alert-dismissible" role="alert">
        <button type="button" class="close" data-dismiss="alert">
            <span aria-hidden="true">&times;</span><span class="sr-only">{{ 'close'|_ }}</span>
        </button>

        <!-- MULTIPLE ERRORS (BAD) -->
        {% if session('error') is iterable and session('error')|length > 1 %}
            <strong>
                {{ Lang.choice('firefly.flash_error_multiple', session('error')|length, {count: session('error')|length}) }}:
            </strong>
            <ul class="list-unstyled">
                {% for err in session('error') %}
                    <li>{{ err }}</li>
                {% endfor %}
            </ul>
        {% endif %}

        <!-- SET OF MULTIPLE ERRORS, BUT THERE IS JUST ONE -->
        {% if session('error') is iterable and session('error')|length == 1 %}
            <strong>{{ 'flash_error'|_ }}</strong>
            {{ session('error')[0]|raw }}
        {% endif %}

        <!-- SINGLE ERROR -->
        {% if session('error') is not iterable %}
            <strong>{{ 'flash_error'|_ }}</strong> {{ session('error')|raw }}
        {% endif %}

    </div>
{% endif %}