Limit react versions to >=15

[danielduan]

Issue:
I don't think our code base supports React ~0.14 anymore. It's been a while since 15 was released and lots has changed in React land. I think it's probably better for us maintenance wise to drop 14 as well.

Either that, or we should have some tests in place to make sure our code base doesn't regress on 14.

This might break support for alpha builds like 16.0.0-alpha.2. We could also document it somewhere in a README about deprecating support instead of in a peer dependency warning that everyone ignores.

Suggestions?

What I did

Seems like we don't support React 0.14 anymore out of the box. Issue came up in support slack and our CRA example app won't take 0.14 either.

How to test

Run CRA example app.

[Hypnosphi]

This might break support for alpha builds like 16.0.0-alpha.2

I believe there is a way not to break that

[ndelangen]

Anyone with a strong opinion on this? who wants to review / approve? @storybooks/team

[codecov]

Codecov Report

Merging #1613 into master will increase coverage by 0.02%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master    #1613      +/-   ##
==========================================
+ Coverage    21.3%   21.32%   +0.02%     
==========================================
  Files         244      244              
  Lines        5384     5378       -6     
  Branches      666      664       -2     
==========================================
  Hits         1147     1147              
+ Misses       3741     3737       -4     
+ Partials      496      494       -2

Impacted Files	Coverage Δ
...-native/src/preview/components/OnDeviceUI/index.js	0% <0%> (ø)	⬆️

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[Hypnosphi]

Looks like it should be >=15.0.0 || ^16.0.0-alpha.

Checked it on http://jubianchi.github.io/semver-check/

16.0.0-beta.5 satisfies constraint >=15.0.0 || ^16.0.0-alpha

[danielduan]

should we implement this across the board in every package.json?

[ndelangen]

With what @Hypnosphi mentions, if we do merge this... we need to explicitly update every time a beta/alpha/rc is released.

[Hypnosphi]

we need to explicitly update every time a beta/alpha/rc is released.

Only after we make sure we support it. And only for later main semver versions (major/minor/patch) than 16.0.0.

[danielduan]

Wouldn't the peerDep just be a warning anyway? I think it will still use any version that's available but complain to you in the console.

[danielduan]

I think one warning on the main react package is probably enough instead of adding it for all the addons. I don't think RN works on react@0.14 so for the time being, * should be fine.

[Hypnosphi]

LGTM