[ARROW-4442] [JS] Overly broad type annotation for Chunked typeId leading to type mismatches in generated typing

• Type: Improvement
• Status: Resolved
• Priority: Minor
• Resolution: Fixed
• Affects Version/s: 0.4.0
• Fix Version/s: 0.13.0
• Component/s: JavaScript
• Labels: pull-request-available
• External issue URL: https://github.com/apache/arrow/issues/21001
• Assignee: Paul Taylor
• Reporter: Paul Taylor
• Created: 31/Jan/19 21:20
• Updated: 11/Jan/23 07:34
• Resolved: 04/Feb/19 21:13

Description

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<T> is Vector<T>:

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.

Issue Links

• links to: GitHub Pull Request #3538