Jade mixin for SVG sprite

_svg-sprite-mixin.jade

mixin sprite(name, title, titleId, desc)

    - var svgAttrObj = {};
    - var titleAttrObj = {};

    if titleId
        - svgAttrObj['aria-labelledby'] = titleId;
        - titleAttrObj['id'] = titleId;

    svg&attributes(svgAttrObj)&attributes(attributes)
        if title
            title&attributes(titleAttrObj) #{title}
        if desc
            desc #{desc}
        use(xlink:href="#sprite-#{name}")