make 'desktop' default device.type or allow setting of default device via option about express-device

[rguerreiro]

When the request comes with an unknown user-agent it returns 'phone' because there's an higher chance that it comes from a mobile device than from a desktop device (new phone OSes and devices appear on a monthly basis).

When there's no user-agent it returns 'desktop' because I'm assuming that it's an unusual situation (tests?) or some sort of an unknown device type. The best behavior (IMO) is to show as if I'm on a desktop.

But I like your suggestion on creating a config option. This way I'll add two: one to return when get an unknown user-agent and other for the default device (to be returned when there isn't an user-agent).

What do you think?

[tbasse]

I like the way that I can set my own device types for both situations now.
But may I suggest you name the options more self-explanatory like this:

unknownUserAgentDeviceType
emptyUserAgentDeviceType

I find your current option names conflictive with your code. If your parser does not match a known agent I would expect it to return the default device type. But your defaultDeviceType would be returned when the user-agent is empty, which is more unlikely than an unknown agent.

[rguerreiro]

done!