Import from ../dataMap in dataMap/index is incorrectly resolving in Liferay's tool

[mrpiotr-dev]

Description

Currently, our dataMap/index reexports DataMap class from the upper directory (by importing it from ../dataMap).
Some tools, such as Liferay used by our clients, interpret ../dataMap, as a reference to the directory not to file:

./core
  import { ... , DataMap } from './dataMap/index'

./dataMap/index
  import DataMap from '../dataMap' // translated as `../dataMap/index`

../dataMap/index has no default export, ending with the hidden problem in ./core because DataMap will be undefined.

Then, when Handsontable initializes a new instance, the load() method tries to create a new undefined.

Steps to reproduce

1. Build package including Handsontable using liferay-npm-bundler with presets for angular
2. Deploy *.jar package as a Liferay's portlet

There are no demo - either steps to reproduce requires the whole env to run, and supposedly we will not be able to reproduce that issue.

Client's environment

• Handsontable version: 8.4.0+
• Browser Name and version: any
• Operating System: any
• node: 10.24.1
• npm: 6.14.12

[aninde]

This issue will be fixed by v10. Tested locally.