Fastify 3.14.1 breaks fastify-websocket Typescript definitions

[mattbishop]

💥 Regression Report

With fastify 3.14.0 and fastify-websocket 3.1.0, one is able to write the following Typescript code to set up a web socket endpoint.

Last working version

Worked up to version: 3.14.0

Stopped working in version: 3.14.1

To Reproduce

Steps to reproduce the behavior:

  const server = fastify()
  server.register(require("fastify-websocket"))

  server.get("/ws", {
    websocket: true
  },
  createWSHandler())
}

When tsc is run, this error is presented:

error TS2345: Argument of type '{ websocket: boolean; }' is not assignable to parameter of type 'RouteShorthandOptions<Server, IncomingMessage, ServerResponse, RouteGenericInterface, unknown, FastifySchema>'.
  Object literal may only specify known properties, and 'websocket' does not exist in type 'RouteShorthandOptions<Server, IncomingMessage, ServerResponse, RouteGenericInterface, unknown, FastifySchema>'.

Expected behavior

tsc should omit no errors.

Your Environment

• node version: 12.21.0
• fastify version: >=3.14.1
• os: Mac 11.2.3
• Typescript 4.2.3

[mcollina]

cc @fastify/typescript

[RafaelGSS]

Can you send your tsconfig.json? The fastify-websocket already has module augmentation for this interface. See: https://github.com/fastify/fastify-websocket/blob/master/index.d.ts#L16

[mattbishop]

Please note this is a Regression report; my code compiles just fine with fastify 3.14.0. I have been using fastify and fastify-websocket in the project for about 1.5 years and upgrade dependencies every week, if that helps.

Before filing this report, I deleted node_modules, yarn.lock and re-installed all dependencies.

Here is the contents of my tsconfig as GitHub won't allow .json attachments:

{
  "compilerOptions": {
    "target": "ES2019",
    "module": "commonjs",
    "outDir": "dist",
    "strict": true,
    "esModuleInterop": true,
    "resolveJsonModule": true,
    "forceConsistentCasingInFileNames": true
  }
}

[zekth]

Looks like there might be a collision somewhere? I tried the type testing using those versions and the types assertions works fine. could you run yarn list --pattern fastify ?

[mattbishop]

Thanks for the suggestion @zekth This is a yarn workspaces project.

yarn list v1.22.10
├─ @fastify/forwarded@1.0.0
├─ @fastify/proxy-addr@3.0.0
├─ consumer-api@0.0.1-snapshot
│  └─ fastify@3.14.1
├─ fastify-error@0.3.0
├─ fastify-etag@2.1.0
├─ fastify-formbody@5.0.0
│  └─ fastify-plugin@2.3.4
├─ fastify-plugin@3.0.0
├─ fastify-warning@0.2.0
├─ fastify-websocket@3.1.0
└─ fastify@3.14.0
✨  Done in 0.32s.

[mattbishop]

I updated a peer module that uses fastify to match (3.14.1) and this issue has been resolved. Thanks again for the suggestions.