fix(core): add missing optional dependencies

[andreialecu]

PR Checklist

Please check if your PR fulfills the following requirements:

• The commit message follows our guidelines: https://github.com/nestjs/nest/blob/master/CONTRIBUTING.md
• Tests for the changes have been added (for bug fixes / features)
• Docs have been added / updated (for bug fixes / features)

PR Type

What kind of change does this PR introduce?

[x] Bugfix
[ ] Feature
[ ] Code style update (formatting, local variables)
[ ] Refactoring (no functional changes, no api changes)
[ ] Build related changes
[ ] CI related changes
[ ] Other... Please describe:

What is the current behavior?

Issue Number: N/A

@nestjs/platform-express is hardcoded as the default platform, and is required in various places in the code base. However, it is not an explicit dependency and thus package installers (yarn/npm/pnpm) need a hint on how to properly link them in order to be resolved.

See:

nest/packages/core/nest-factory.ts

Lines 211 to 218 in 09fbc83

	private createHttpAdapter<T = any>(httpServer?: T): AbstractHttpAdapter {
	const { ExpressAdapter } = loadAdapter(
	'@nestjs/platform-express',
	'HTTP',
	() => require('@nestjs/platform-express'),
	);
	return new ExpressAdapter(httpServer);
	}

Without this change, Nest has problems running on stricter package managers (yarn with pnp, or pnpm)

What is the new behavior?

@nestjs/platform-express is added as an optional dependency. peerDependenciesMeta is supported by all major package managers: npm, yarn and pnpm.

Does this PR introduce a breaking change?

[ ] Yes
[x] No

Other information

See: https://yarnpkg.com/advanced/rulebook#packages-should-only-ever-require-what-they-formally-list-in-their-dependencies

[coveralls]

Pull Request Test Coverage Report for Build b6459367-ea49-40fc-b5bb-8ffd4337ae59

• 0 of 0 changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 94.825%

---

Totals
Change from base Build cf4f5692-9ee1-4371-8130-5c6f9c02faac:	0.0%
Covered Lines:	4929
Relevant Lines:	5198

---

💛 - Coveralls

[kamilmysliwiec]

We should probably add @nestjs/microservices and @nestjs/websockets as well as they are referenced in the codebase

[andreialecu]

@kamilmysliwiec shall I add them as part of this same PR?

[kamilmysliwiec]

@andreialecu sounds good!

[andreialecu]

Added.

[andreialecu]

It seems that class-validator and class-transformer may also need to be added:

nest/packages/common/pipes/validation.pipe.ts

Lines 63 to 68 in 85c6be1

	classValidator = loadPackage('class-validator', 'ValidationPipe', () =>
	require('class-validator'),
	);
	classTransformer = loadPackage('class-transformer', 'ValidationPipe', () =>
	require('class-transformer'),
	);

Originally reported at: nestjs/nest-cli#555 (comment)

Probably everything else that comes up in other calls to loadPackage(...) may need to go through the same treatment as well.

[andreialecu]

It might worth it to explore whether this eslint rule can be implemented:
https://github.com/benmosher/eslint-plugin-import/blob/master/docs/rules/no-extraneous-dependencies.md

[kamilmysliwiec]

@andreialecu

Probably everything else that comes up in other calls to loadPackage(...) may need to go through the same treatment as well.

Would you like to do it in this PR?

[andreialecu]

@kamilmysliwiec done.

I used npx @yarnpkg/doctor . to find them all (see: https://yarnpkg.com/getting-started/migration#run-the-doctor)

There are still a bunch of warnings left, but they're internal to the project (dev dependencies, etc) so I didn't mess with those (since they won't affect end users of packages). They can be fixed as part of a subsequent PR.

[andreialecu]

@kamilmysliwiec just some further info:

All recent package managers support optional peer dependencies using the peerDependenciesMeta field:

npm as of: npm/cli#224
Yarn 1: https://classic.yarnpkg.com/en/docs/package-json#toc-peerdependenciesmeta
Yarn 2: https://yarnpkg.com/configuration/manifest/#peerDependenciesMeta
pnpm: https://pnpm.js.org/en/package_json#peerdependenciesmeta

[andreialecu]

This one is actually not optional, see:

nest/packages/websockets/index.ts

Line 7 in 8e216b2

import 'reflect-metadata';

[andreialecu]

Not optional, see:

nest/packages/microservices/index.ts

Line 7 in 8e216b2

import 'reflect-metadata';

[andreialecu]

Also relevant: moleculerjs/moleculer#623 (comment)

[andreialecu]

@kamilmysliwiec is there anything holding this from being merged? There have been a bunch of support requests in the Yarn discord related to NestJS not working properly out of the box and this is among the last things needed.

[stylemistake]

We use yarn berry with workspaces, but without the monorepo flag set in nest-cli. If using typescript compiler, it works even without that huge of a list of peer dependency overrides, but it becomes a massive problem with webpack flag set.

Some peer dependencies that might be missing from this PR:

  "@nestjs/mapped-types@*":
    peerDependenciesMeta:
      "class-transformer":
        optional: true
      "class-validator":
        optional: true
  "@nestjs/serve-static@*":
    peerDependenciesMeta:
      "express":
        optional: true
  "@nestjs/swagger@*":
    peerDependenciesMeta:
      "swagger-ui-express":
        optional: true