[FEATURE] Allow piping into semver to read version

[felixfbecker]

It would be very nice if we could do this:

node -v | semver -r ^5.4

Of course one could do semver $(node -v) but that only works in sh and not on Windows, which makes it bad for npm scripts.

[isaacs]

I'm ok with it. Patch welcome, as long as it includes docs and test :)

[felixfbecker]

Great. Is it possible to "detect" if there is data being piped from stdin or is a new command line flag needed?

[isaacs]

You can check process.stdin.isTTY and also default to stdin if - is an option or if no options are provided. The stdin stream should be a white space delimited set of versions, probably?

[felixfbecker]

You can check process.stdin.isTTY

thanks.

The stdin stream should be a white space delimited set of versions, probably?

I agree.

There is no engine field in package.json. What node versions have to be supported? I guess no arrow functions?

[felixfbecker]

I guess the whitespace splitting will not work completely because one version can contain spaces, like ">=0.2 <=0.8". I guess the only option is to split by line breaks?

[isaacs]

@felixfbecker Those are version ranges, not versions.

I'm imagining a thing like this:

get-list-of-versions-somehow | semver -r '>=2' > file-with-versions-gt-two.txt

So, the list of versions can be piped to stdin, but not the set of ranges

[gWOLF3]

can we merge this?