[node] Unable to import from "schematic-class/esm/jsonclass.js" as an ES module

[t2ym]

[node] Unable to import from "schematic-class/esm/jsonclass.js" as an ES module

Root Cause

• On node, extensions must be .mjs for ES modules of no type section package when the file path is specified
• This behavior can be thought as expected

Error - reproducible with 0.0.9

import { JSONClass, JSONClassError } from 'schematic-class/esm/jsonclass.js';
         ^^^^^^^^^
SyntaxError: Named export 'JSONClass' not found. The requested module 'schematic-class/esm/jsonclass.js' is a CommonJS module, which may not support all module.exports as named exports.
CommonJS modules can always be imported via the default export, for example using:

import pkg from 'schematic-class/esm/jsonclass.js';
const { JSONClass, JSONClassError } = pkg;

Workaround

• import { JSONClass, JSONClassError } from "schematic-class"

Fix Candidates

• Option 1: Add redundant "schematic-class/esm/jsonclass.mjs" as a copy of "schematic-class/esm/jsonclass.js"

• Option 2: Specify an effective "exports" section in package.json without regression for [npm] Unable to import as ES module #6

• "type": "module" is effective but harmful to CommonJS import

• This configuration does not work

  "main": "jsonclass.js",
  "module": "esm/jsonclass.js",
  "exports": {
    ".": {
      "import": "./esm/jsonclass.js",
      "require": "./jsonclass.js"
    },
    "./esm/jsonclass.js": {
      "import": "./esm/jsonclass.js"
    }
  },

Notes

• "schematic-class" on node and browser with importmap
• "/node_modules/schematic-class/esm/jsonclass.js" on browser without importmap