Support `next` as npm tag in `--scripts-version`

[miraage]

Not sure if it is a bug or not (might be intented behavior).
Instead of writing ... --scripts-version=2.0.0-next.66cc7a90 we would write ... -scripts-version=next.

Currently it installs zeit/next.js.

// EDIT

Possible solution might touch a single line:

- if (validSemver) {
+ if (validSemver || version === 'next') {

Not sure how "breaking" this change might be.

[gaearon]

Currently it installs zeit/next.js.

😄

Possible solution might touch a single line:

It's odd to treat next specifically in a different way. Maybe we can support @next (i.e. treat @ as beginning of npm tag)?

[miraage]

Sounds good to me. Kinda explicit package version.

[Timer]

Do you want to send a PR?

[miraage]

@Timer I can do it. I have a question regarding resolving package version. I see a few options:

1. simply check if the first character is @ and string length is greater than 1 (semver.valid returns false if we pass next).
2. check for a valid versions using npm view react-scripts@next version. It has 3 kind of responses (ok, package 404, bad tag). There is also some options:

• 2.1. fallback to the latest stable tag (silently or with a warning?)
• 2.2. throw an error

/cc @gaearon

[miraage]

There is an issue with yarn: version outputs as is.

$ yarn info react-scripts@next version --silent
> next

https://github.com/yarnpkg/yarn/blob/v1.6.0/src/cli/commands/info.js#L77

We might want

- result.version = version || result['dist-tags'].latest;
+ result.version = result['dist-tags'][version] || version || result['dist-tags'].latest;

Should I open a PR there?

[Timer]

I'm guessing just a simple check; if the string starts with @ just do .substring(1) and treat that as the version (the same way 2.0.0-next.66cc7a90 is).

[miraage]

It makes sense since other options are not validated as well (e.g. file: or .tar.gz). WIP.