jfparadis / rollup-esm-test

Test of Rollup with native ESM module

Test of Rollup with native ESM module

• Rollup Version: 1.27.5
• Operating System (or Browser): MacOS
• Node Version (if applicable): v13.6.0
• Link to reproduction (IMPORTANT, read below): https://github.com/jfparadis/rollup-esm-test

Module support in node is still in early stages (and maybe not ready for runtime), but there are benefits to use it in a tool chain, and to begin creating packages with native support:

• to get the native behavior of JS in tests
• to avoid caching issues with esm transpilation

Numerous options are possible as documented here: https://github.com/nodejs/node/blob/master/doc/api/esm.md#approach-1-use-an-es-module-wrapper

Expected Behavior

This form should be usable from a package with native ESM support:

import { rollup } from 'rollup';

As verifiable via a simple command-line test:

node  --input-type=module -e "import { rollup } from 'rollup'; console.log(typeof rollup)"
function

Or as verifiable in context of the test package provided:

git clone https://github.com/jfparadis/rollup-esm-test.git
cd rollup-esm-test
npm install

npm test

# rollup
ok 1 should be equal

1..1
# tests 1
# pass  1

# ok

Actual Behavior

Error, as verifiable via a simple command-line test:

node  --input-type=module -e "import { rollup } from 'rollup';"
import { rollup } from 'rollup';
         ^^^^^^
SyntaxError: The requested module 'rollup' does not provide an export named 'rollup'

Or as verifiable in the context of the test package provided:

git clone https://github.com/jfparadis/rollup-esm-test.git
cd rollup-esm-test
npm install
npm test
import { rollup } from 'rollup';
         ^^^^^^
SyntaxError: The requested module 'rollup' does not provide an export named 'rollup'

Workaround

The workaround is to use a wrapper or an alternate syntax to resolve the exports:

import cjsRollup from 'rollup';
const { rollup } = cjsRollup;

As verifiable via a simple command-line test:

node  --input-type=module -e "import cjsRollup from 'rollup'; const { rollup } = cjsRollup; console.log(typeof rollup)"
function

Or as verifiable the in context of the test package provided, by commenting and uncommenting a few lines in test.js.