fuse-box/modules/fuse-box-css/index.js

Fuse-Box a bundler that does it right

/**
 * Listens to 'async' requets and if the name is a css file
 * wires it to `__fsbx_css`
 */
if (typeof FuseBox !== "undefined" && FuseBox.isBrowser) {
    FuseBox.on('async', function(name) {
        if (FuseBox.isServer) {
            return;
        }
        if (/\.css$/.test(name)) {
            __fsbx_css(name);
            return false;
        }
    });
}

module.exports = function(__filename, contents) {
    if (!FuseBox.isServer) {
        var styleId = __filename.replace(/[\.\/]+/g, '-');
        if (styleId.charAt(0) === '-') styleId = styleId.substring(1);
        var exists = document.getElementById(styleId);
        if (!exists) {
            //<link href="//fonts.googleapis.com/css?family=Covered+By+Your+Grace" rel="stylesheet" type="text/css">
            var s = document.createElement(contents ? 'style' : 'link');
            s.id = styleId;
            s.type = 'text/css';
            if (contents) {
                s.innerHTML = contents;
            } else {
                s.rel = 'stylesheet';
                s.href = __filename;
            }
            document.getElementsByTagName('head')[0].appendChild(s);
        } else {
            if (contents) {
                exists.innerHTML = contents;
            }
        }
    }
}