rf-web/_includes/common/lang-selector.html

{% assign posts=site.posts | where:"ref", page.ref | sort: 'lang' %}
{% assign pages=site.pages | where:"ref", page.ref | sort: 'lang' %}

<div class="nav-group lang-selector">
    {% if posts.size > 1 %}
        {% for post in posts %}
            {% if post.lang != page.lang %}
                <a href="{{ site.base-url }}{{ post.url }}" class="lang lang--{{ page.lang }}">
                    {% if page.lang == 'en' %}
                        {{ include.fr-text }}
                    {% else %}
                        {{ include.en-text }}
                    {% endif %}
                </a>
            {% endif %}
        {% endfor %}

    {% elsif pages.size > 1 %}
        {% for newpage in pages %}
            {% if newpage.lang != page.lang and page.ref != '' %}
                    {% if page.lang == 'en' %}
                        <a href="{{ newpage.url }}" class="lang lang--{{ page.lang }}">{{ include.fr-text }}</a>
                    {% else %}
                        <a href="{{ newpage.url }}" class="lang lang--{{ page.lang }}">{{ include.en-text }} </a>
                    {% endif %}
            {% endif %}
        {% endfor %}


    {% elsif page.lang == 'en' %}
        <a href="/fr" class="lang lang--{{ page.lang }}">{{ include.fr-text }}</a>
    {% else %}
        <a href="/" class="lang lang--{{ page.lang }}">{{ include.en-text }} </a>
    {% endif %}
</div>