fix CJS & ESM distribution

[JakobJingleheimer]

Summary

Previously, react-merge-refs was distributing both CJS and ESM, which is unnecessary (ESM can import CJS just fine). Additionally the package.json was not properly configured to publicise the ESM distribution.

Now, only CJS is built and distributed, and package.json properly publicises both for use by either CJS or ESM.

Fixes #16

Test plan

These should both return { default: [Function: mergeRefs] } (they fail on main, but succeed on this branch).

$ node \
--input-type=module \
-e "import mergeRefs from 'react-merge-refs'; console.log(mergeRefs)"

$> node \
--input-type=commonjs \
-e "const mergeRefs = require('react-merge-refs'); console.log(mergeRefs)"

This should not be a breaking change.

[Benjamin-Willard]

FYI this merge broke.

Uncaught Error Error [ERR_REQUIRE_ESM]: require() of ES Module D:\@blender\suicideleague\@app\node_modules\react-merge-refs\dist\index.mjs not supported.
Instead change the require of D:\@blender\suicideleague\@app\node_modules\react-merge-refs\dist\index.mjs to a dynamic import() which is available in all CommonJS modules.

I am using SSR and this is caught on the server side compiling with webpack

[JakobJingleheimer]

FYI this merge broke.

Uncaught Error Error [ERR_REQUIRE_ESM]: require() of ES Module D:\@blender\suicideleague\@app\node_modules\react-merge-refs\dist\index.mjs not supported.

Instead change the require of D:\@blender\suicideleague\@app\node_modules\react-merge-refs\dist\index.mjs to a dynamic import() which is available in all CommonJS modules.

I am using SSR and this is caught on the server side compiling with webpack

It was an intentional choice of the package owner to break compatibility with CJS. You can follow the error message's suggestion to consume it in CJS.

Please see the release notes of the semver major bump specifically mentioning the breaking change: https://github.com/gregberge/react-merge-refs/releases/tag/v2.0.0