Fallback Icon for Navigation Bar about wren HOT 1 CLOSED

This turned out to be a non-trivial issue. Icons are brought into navigation bar using

<svg>
    <use xlink:href="/path/to/icons.svg#$ID"></use>
</svg>

Even if there's no <symbol id=$ID> in icons.svg, the server doesn't display a 404 error and instead just displays an empty icon. That means there's no straightforward way to check whether an icon is going to exist before, during, or after the HTML pulls it without maintaining another explicit list of the icons covered.

One way to skirt around this issue would be to switch both icon-sheets to instead be directories of icons to be called by filename rather than SVG's symbol.id property. These can then be existence checked before loading using stock liquid syntax.

{% for static_file in site.static_files %}
    {% if static_file.path == '/favicon.ico' %}
        {% assign favicon = true %}
    {% endif %}
{% endfor %}

from wren.