fix(deps): add optional peer deps into peerDependencies

[kyletsang]

In the NPM docs, optional peer deps should be specified in peerDependencies because this is where the versioning info comes from. This is the example from the NPM docs:

{
  "name": "tea-latte",
  "version": "1.3.5",
  "peerDependencies": {
    "tea": "2.x",
    "soy-milk": "1.2"
  },
  "peerDependenciesMeta": {
    "soy-milk": {
      "optional": true
    }
  }
}

One thing I wasn't sure about was the react native compatibility, so I placed the version that's currently in devDeps as a placeholder. I'll fix this once I get confirmation.

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[markerikson]

I really don't think we want to do this, especially given how NPM currently insists on installing those automatically and throws errors if there's a mismatch.

@timdorr , @Methuselah96 : thoughts here?

[markerikson]

We've specifically rejected this change several times in the past:

• fix: List optional peer dependencies #1390
• Adds react-dom and react-native as optional peer dependencies #1425

(and see related links)

But I do see some mentions of NPM 6 in those threads, so not entirely sure where things stand on that now.

[kyletsang]

Does the peerDepsMeta field actually work with the package version info missing from the peerDeps field? My understanding was these were to go hand in hand.

I believe the NPM 6 functionality was to warn in the console. NPM 7+ will try to resolve the dependencies and reject if peer deps aren't installed, but specifying "optional" in the peerDepsMeta field should bypass that.

[Methuselah96]

I think this is correct and what we want. I believe all the previous issues/PRs were created before NPM properly supported optional peer dependencies which is why they were appropriately rejected at the time, but now all the package managers should fully support optional peer dependencies. My understanding is that npm 7+ will not install optional peer dependencies automatically, however I don't actively use npm, so it might be worth double-checking that this works as expected on npm 6 and npm 7+.

[markerikson]

Thank you!