YSlow.js is installed in the code base by default, however, on installation an install script is run to ensure that the pathing is setup correctly. This install script does not support Windows.
yslow.js is in the Mac / Linux format. As a
workaround you should be able to simply add the following
YSlow.js isntallation isn't supported on Windows. See http://yslow.org/phantomjs for Windows installation instructions.
var YSlow = require('yslowjs'); YSlow.prototype.script = '/path/to/yslow.js';
If this doesn't work, the failover is to isntall
(http://yslow.org/phantomjs) and specify the path as shown