title: Building CJS module from ESM with mixed named and default export - how to omit 'default'?
body: <p>I am trying to configure rollup to build commonjs module from existing esm.
  I have set of separate standalone methods, exported with <code>default</code> and available to import directly from package like:</p>
  <pre><code>import method1 from 'lib/method1'
  </code></pre>
  <p>And I have single entry point for all of them <code>standalone.js</code> to let user code import them separately using destructuring or at once as lib.</p>
  <pre class="lang-js prettyprint-override"><code>import _method1 from './method1'
  import _method2 from './method2'
  import _method3 from './method3'
  
  export const method1 = _method1;
  export const method2 = _method2;
  export const method3 = _method3;
  
  export default {method1,method2,method3};
  </code></pre>
  <p>So this is usage example:</p>
  <pre class="lang-js prettyprint-override"><code>import method1 from 'lib/method1'
  //or
  import { method1 } from 'lib/standalone'
  //or
  import standalone from 'lib/standalone'
  //standalone.method1();
  </code></pre>
  <p>All this works fine for esm and I want similar experience for cjs.
  Rollups do everything almost correct but it's complaining about mixed named/default export and adding extra <code>module.exports.default</code> field:</p>
  <pre class="lang-js prettyprint-override"><code>'use strict';
  
  Object.defineProperty(exports, '__esModule', { value: true });
  
  var condense$1 = require('./condense.js');
  var condenseDeep$1 = require('./condenseDeep.js');
  var eachDeep$1 = require('./eachDeep.js');
  // ...
  
  
  var condense = condense$1;
  var condenseDeep = condenseDeep$1;
  var eachDeep = eachDeep$1;
  //...
  
  var standalone = {
    condense: condense$1,
    condenseDeep: condenseDeep$1,
    eachDeep: eachDeep$1,
    //...
  };
  
  exports.condense = condense;
  exports.condenseDeep = condenseDeep;
  exports.default = standalone; // &lt;-- this one, how to remove it?
  exports.eachDeep = eachDeep;
  //...
  </code></pre>
  <p>so in commionjs usage looks like:</p>
  <pre class="lang-js prettyprint-override"><code>const method1 = require('lib/method1');
  //or
  const { method1 } = require ('lib/standalone');
  //or
  const standalone = require('lib/standalone');
  //standalone.method1();
  //standalone.default &lt;--- this is redundant and confusing
  </code></pre>
  <p>I tried <code>output.exports: 'named'</code> rollup option - other entry points which are using default only also started having <code>module.exports.default = ..</code> instead of expected <code>module.exports = ..</code></p>
  <p>I tried <code>output.exports: 'default'</code> - it's not working with mixed default/named exports, throwing error.</p>