title: SystemJS, using importmap with module, that needs react
body: <p>I have created a javascript library with webpack, that outputs a systemjs module. This module has a dependency on react, which I specified as an external.
  The resulting javascript file starts like this:</p>
  
  <pre><code>System.register(["react"], function(__WEBPACK_DYNAMIC_EXPORT__) {
  var __WEBPACK_EXTERNAL_MODULE_react__;
  return { ....
  </code></pre>
  
  <p>Additionally I have an app, that uses SystemJS during runtime to load that module. In order to provide the react dependency, I have defined an importmap:</p>
  
  <pre><code>{
     "imports": {
        "react": "https://unpkg.com/react@16.11.0/umd/react.production.min.js"
     }
  }
  </code></pre>
  
  <p>And the part, where I import the module, looks like this:</p>
  
  <pre><code>const modulePromise = System.import(MODULE_URL);
  modulePromise.then(module =&gt; {
    console.log('module loaded successfully!');
  });
  </code></pre>
  
  <p>The problem now is, that the console.log is never called, because I get a TypeError, that says, that "Component is not a property of undefined", which tells me, that somehow react has not correctly been passed to my module.</p>
  
  <p>To be precise, in the browser network tab I see, that my module and the react import is indeed loaded, but somehow it is not correctly processed.</p>
  
  <p>Has anyone an idea, what i might be doing wrong?</p>