title: Default function export type definition
body: <p>I'm attempting to write a typing definition for <a href="https://github.com/pgte/pouch-redux-middleware" rel="noreferrer">pouch-redux-middleware</a>, which exports a single function: </p>
  
  <pre><code>import PouchMiddleware from 'pouch-redux-middleware'
  
  PouchMiddleware({...})
  </code></pre>
  
  <p>Here is the typings definition I have:</p>
  
  <pre><code>interface PouchMiddleware {
    (a: any): any;
  }
  
  declare var PouchMiddleware: PouchMiddleware;
  
  declare module "pouch-redux-middleware" {
    export = PouchMiddleware;
  }
  </code></pre>
  
  <p>This results in the error:</p>
  
  <blockquote>
    <p>Module '"pouch-redux-middleware"' has no default export.</p>
  </blockquote>
  
  <p>What is the correct way to declare this?</p>