Packages not specified as modules

[mattrunyon]

Description

Packages do not specify they are modules in their package.json files. This causes node to break if you try to import something like utils to use elsewhere (docs script, for example).

Since we only publish ESM for all packages (except code-studio and golden-layout), we should add type: "module" to our package.json files to indicate to Node that the .js extension is to be treated as ESModules and not CommonJS.

Steps to reproduce
Run the following script with Node 14 (saved as a js file)

const { GridUtils } = import('@deephaven/grid');
console.log(GridUtils);

or this saved as a mjs file

import { GridUtils } from '@deephaven/grid';
console.log(GridUtils);

Expected results

Console log of GridUtils object

Actual results

Errors about unexpected import/export or expecting module type CommonJS

Versions

• Deephaven: 0.3.1
• Node: 14.12.0

[mattrunyon]

Apparently this will also need some babel plugin to add file extensions to our imports for the dist code. ESM mandates file extensions with imports in the spec. Most tools we use have something built-in to handle this for us, but using without any build systems (which was part of the point of publishing ESM) the files should have extensions

https://nodejs.org/api/esm.html#esm_mandatory_file_extensions