Types from packages are not properly used when checking JS with esModuleInterop

[stof]

TypeScript Version: 3.8.0-dev.20191119 (same result with 3.7.2 as well)

Search Terms: types checkJS

Code

{
  "dependencies": {
    "humane-js": "3.2.2"
  },
  "devDependencies": {
    "@types/humane-js": "3.2.0",
    "typescript": "3.8.0-dev.20191119"
  }
}

// typescript.ts
import humane from 'humane-js';

humane.timeout = 4000;

export const notifyInfo = humane.spawn({ addnCls: 'humane-info' });

// javascript.js (same code than typescript.ts)
import humane from 'humane-js';

humane.timeout = 4000;

export const notifyInfo = humane.spawn({ addnCls: 'humane-info' });

Expected behavior:

Running both tsc --noEmit --esModuleInterop typescript.ts and tsc --noEmit --esModuleInterop --allowJS --checkJS javascript.js succeed.

Actual behavior:

Type-checking for the Typescript file succeeds. But type-checking for the javascript files fails with this error:

javascript.js:5:34 - error TS2339: Property 'spawn' does not exist on type 'typeof humane'.

5 export const notifyInfo = humane.spawn({ addnCls: 'humane-info' });
                                   ~~~~~


Found 1 error.

Note that if I change my JS file to use a CommonJS require call rather than an ES import and then run tsc --noEmit --allowJS --checkJS javascript.js, tsc will properly identify the type of humane (type-checking succeeds on this code, and introducing a typo in the spawn method name gets caught)

It would be great if --esModuleInterop could work when using tsc to check JS code, to allow using it to check webpack projects (which have such interop loading of JS modules).

[rbuckton]

This seems to have been fixed by #39490 while I was making other changes.

[rbuckton]

@stof can you verify this with tomorrows nightly to make sure it has been properly addressed?

[andrewbranch]

Confirmed.