Native optional devDependencies trick with npm workspaces

Since `npm install` automatically uses your `package.json`'s `workspaces: [ ... ]` value to install all workspaces at once, you can take advantage of this with a subfolder that has a `package.json` like:

```jsonc
// optionalDevDependencies/package.json
{
"optionalDependencies": {
"my-optional-dev-dependency": "^1.2.3"
}
}
```

and then the root package.json like:

```jsonc
{
"name": "my-awesome-package-with-optional-dev-dependencies",
"version": "4.5.6",
"optionalDependencies": {
"my-optional-production-dependency": "^10.11.12"
},
"devDependencies": {
"my-required-dev-dependency": "^7.8.9"
}
"workspaces": ["optionalDevDependencies"]
}
```

That way when you run `npm install` it will install the stuff from `./optionalDevDependencies/package.json`'s `optionalDependencies`, BUT when you `npm publish` it the workspace gets completely ignored and the only things left in the manifest are the required devDependencies and the production optionalDependencies.

I think this is a pretty cool trick! I used it to add all the esbuild targets as optional devDependency items for some testing of raw esbuild binary stuff. I needed some optional devDependency items so that npm would choose the right package for the os/cpu combo

```jsonc
// optionalDevDependencies/package.json
{
"optionalDependencies": {
"@esbuild/aix-ppc64": "0.19.11",
"@esbuild/android-arm": "0.19.11",
"@esbuild/android-arm64": "0.19.11",
"@esbuild/android-x64": "0.19.11",
"@esbuild/darwin-arm64": "0.19.11",
"@esbuild/darwin-x64": "0.19.11",
"@esbuild/freebsd-arm64": "0.19.11",
"@esbuild/freebsd-x64": "0.19.11",
"@esbuild/linux-arm": "0.19.11",
"@esbuild/linux-arm64": "0.19.11",
"@esbuild/linux-ia32": "0.19.11",
"@esbuild/linux-loong64": "0.19.11",
"@esbuild/linux-mips64el": "0.19.11",
"@esbuild/linux-ppc64": "0.19.11",
"@esbuild/linux-riscv64": "0.19.11",
"@esbuild/linux-s390x": "0.19.11",
"@esbuild/linux-x64": "0.19.11",
"@esbuild/netbsd-x64": "0.19.11",
"@esbuild/openbsd-x64": "0.19.11",
"@esbuild/sunos-x64": "0.19.11",
"@esbuild/win32-arm64": "0.19.11",
"@esbuild/win32-ia32": "0.19.11",
"@esbuild/win32-x64": "0.19.11"
}
}
```

This isn't really an issue. This is me trying to share this trick that I found that I thought was cool with anyone else who comes across the https://www.npmjs.com/package/optional-dev-dependency package (which is deprecated) or this github repository looking for a way to do optional dev dependencies. 😊
Feel free to close this if this is the wrong place for such stuff. ❤️

Beginne mit den Beispielen in root package.json und optionalDevDependencies/package.json und überprüfe anschließend das beschriebene Verhalten von npm install und npm publish, falls die Maintainer beschließen, den Trick zu dokumentieren. Als erledigt würde eine ausdrückliche Anfrage nach Dokumentation oder Code gelten; dieser Bericht enthält derzeit keines von beidem.

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