Jade meta tag mixin

meta.jade

mixin meta(name, content)
    -
        var attrs = {};
        var httpEquivRegExp = /^content-(?:encoding|length|language|type|(?:style|script)-type)|default-style|refresh|set-cookie|pragma|cache-control|expires|allow|date|last-modified|location|www-authenticate|x-(?:ua-compatible|dns-prefetch-control|rim-auto-match)$/i;
        var ogpRegExp = /^og:/i;
        name = typeof name === "string" ? name.trim() : null;
        content = typeof content === "string" ? content.trim() : null;

    if name && content

        if name === "charset"
            meta(charset="#{content}")&attributes(attributes)
        else
            if httpEquivRegExp.test(name)
                - attrs["http-equiv"] = name;
            else if ogpRegExp.test(name)
                - attrs["property"] = name;
            else
                - attrs["name"] = name
            meta(content="#{content}")&attributes(attrs)&attributes(attributes)