[JS] Overly broad type annotation for Chunked typeId leading to type mismatches in generated typing

[asfimport]

Typescript is generating an overly broad type for the typeId property of the ChunkedVector class, leading to a type mismatch and failure to infer Column is Vector:

let col: Vector<Utf8>;
col = new Chunked(new Utf8());
  ^
/*
Argument of type 'Chunked<Utf8>' is not assignable to parameter of type 'Vector<Utf8>'.
  Type 'Chunked<Utf8>' is not assignable to type 'Vector<Utf8>'.
    Types of property 'typeId' are incompatible.
      Type 'Type' is not assignable to type 'Type.Utf8'.
*/

The fix is to add an explicit return annotation to the Chunked typeId getter.

Reporter: Paul Taylor / @trxcllnt
Assignee: Paul Taylor / @trxcllnt

PRs and other links:

• GitHub Pull Request #3538

_{Note: This issue was originally created as ARROW-4442. Please see the migration documentation for further details.}

[asfimport]

Wes McKinney / @wesm:
Issue resolved by pull request 3538
#3538