• Rollup Plugin Name: @rollup/plugin-commonjs
• Rollup Plugin Version: 21.0.0

Expected Behavior / Situation

If an ESM file is transformed with transformMixedEsModules=true (for require support), it shouldn't replace typeof exports by 'object' and leave it as-is (or replace by 'undefined' ?)

Actual Behavior / Situation

Right now the bundle fails with exports is not defined because of code in ESM such as lodash-es:
https://github.com/lodash/lodash/blob/es/isBuffer.js#L5

var freeExports = typeof exports == 'object' && exports && !exports.nodeType && exports;
// becomes:
var freeExports = exports && !exports.nodeType && exports;

(lodash-es itself doesn't require transformMixedEsModules, but other parts of the bundle do)

Modification Proposal

If esModule=true do not transform typeof module/exports/module.exports into 'object', as they'll likely open invalid code paths in an ESM.

(I can PR with tests if agreed)