Extract StdinDiscarder into separate library

[ffMathy]

It would be super useful to use separately.

[sindresorhus]

// @stroncium

[stroncium]

Yeah, no prob. Though probably on coming weekend, have to make money for now 😢.

[Richienb]

@sindresorhus To speed up the completion of this issue, I'll extract the code if you wish.

[sindresorhus]

I would prefer if @stroncium did it as he's the one with the most experience about all the edge-cases.

[stroncium]

Yeah, that sounds like a good idea, that thing can be quite tricky. Sorry for delay, a lot of irl stuff happening. I'll get to it asap.

[sindresorhus]

@stroncium I have now extracted it to a separate package: https://github.com/sindresorhus/stdin-discarder

However, I noticed some things:

• The following seems to be dead code. There's nothing that uses it: https://github.com/sindresorhus/stdin-discarder/blob/a367682430700a0528905b7dda045f1dbf87a3b8/index.js#L17-L32
• After extracting the code, I noticed that it does not actually prevent stdin even in Ora before extracting the code. However, it seems the stdin prevention worked before Fix discardStdin option #135.

[stroncium]

I will look into it, but at the time of fix it was clearly working. Probably have to do with some undocumented details of node(which I had some fair fights with working on this thing).