Wrong declaration file generated for JS + subclass

[Jack-Works]

TypeScript Version: 3.7.x-dev.201xxxxx

Search Terms:

Code

src/tsconfig.json

{
  "compilerOptions": {
    "allowJs": true,
    "declaration": true,
    "emitDeclarationOnly": true,
    "declarationDir": "../dts/"
  }
}

src/index.js (Important, this only happens in .js file)

export class A {
  /** @returns {this} */
  method() {}
}
export default class Base extends A {
  // This method is required to reproduce this bug
  verify() {}
}

Expected behavior:

Generated .d.ts:

export declare class A {
    /** @returns {this} */
    method(): void;
}
export default class Base extends A {
    verify(): void;
}

Actual behavior:

export class A {
    /** @returns {this} */
    method(): A;
}
export default class Base extends A {
    verify(): void;
    /** @returns {this} */
    method(): Base;
}

The wrong behavior:

1. Methods from the parent class is copied to the subclass
2. The return type of copied class is wrong (should be this, actually the class name.)

This behavior cause the error following:

(The parent class is import('events').EventEmitter)

[chriswoodle]

Looks like I have same issue:
https://github.com/chriswoodle/typescript-allowjs-eventemitter-bug

[Jack-Works]

Hmm do you sure it get fixed? When I doing code gen in 4.0.0-dev-20200505 it still exists

[weswigham]

Is there a second issue? we have your repro, almost verbatim, in our test suite now

[Jack-Works]

Oh strange I can't reproduce it by a POC

[Jack-Works]

> const m = require('ts-morph')
> m.ts.version
'3.8.3'
> const ts = require('typescript')
> ts.version
'4.0.0-dev.20200505'
>

It's a dependency problem, sorry! 🤣