TypeScript error "Unable to resolve signature of parameter decorator when called as an expression"

[ozelen]

On the sample code:

import { Injectable } from '@nestjs/common';
import { Counter } from 'prom-client';
import { InjectMetric } from '@willsoto/nestjs-prometheus';

@Injectable()
export class Service {
  constructor(@InjectMetric('metric_name') public counter: Counter<string>) {}
}

TS compiler throws an error:

Unable to resolve signature of parameter decorator when called as an expression.
  Argument of type 'typeof Service' is not assignable to parameter of type 'Record<string, unknown>'.
    Index signature for type 'string' is missing in type 'typeof Service'

[willsoto]

What version of TypeScript?

[ozelen]

@willsoto , 4.3.5

[willsoto]

Works for me on TS 4.9.5

4.3.5 is a very old version of TypeScript though. You should try upgrading and, if it's still broken, creating a minimal reproduction or a failing test case.

[ozelen]

Agree. I updated TS version. Still see the error, but it's only visible in VSCode, not runtime. Like follows

[willsoto]

Try reloading VSCode?

[ozelen]

tried already, didn't help though. Weird thing...

[willsoto]

Perhaps VSCode isn't using whatever tsconfig the runtime is using?

[ozelen]

Looks like the plugin JavaScript and TypeScript Nightly works incorrectly. When I turned it off, the problem disappeared (along with some validation hinting though :), but VSC started performing much better).

[willsoto]

👍

[nstoya]

With typescript v5 it fails with the same error when trying to build.

[willsoto]

Please confirm it's not the same issue with the same resolution mentioned here: #1667 (comment)

If you believe it's actually an issue with v5, please open a new issue with a minimal reproduction of the problem.

[Nicklason]

Please confirm it's not the same issue with the same resolution mentioned here: #1667 (comment)

If you believe it's actually an issue with v5, please open a new issue with a minimal reproduction of the problem.

I have the same problem. This reproduces the problem. I have also fixed the problem and I am making a pull request for it right now.

[willsoto]

🎉 This issue has been resolved in version 5.1.1 🎉

The release is available on:

• GitHub release
• npm package (@latest dist-tag)

Your semantic-release bot 📦🚀