title: Koa-router route urls that don't exist
body: <p>I can't believe there is no easy answer to do this.
  I wish to redirect let's say;</p>
  
  <pre><code>www.example.com/this-url-does-not-exist
  </code></pre>
  
  <p>to</p>
  
  <pre><code>www.example.com/
  </code></pre>
  
  <p>There has to be a way, all the nodejs websites with koajs just can't crash? Heres my router (I'm using koa with koa-router):</p>
  
  <pre><code>router
      .get('/', function* (next) {
          this.body = "public: /";
      })
      .get('/about', function* (next) {
          this.body = "public: /about";
      })
      .get('*', function* (next) { // &lt;--- wildcard * doesn't work
          this.body = "public: *";
      });
  </code></pre>
  
  <p>And don't tell me to use regular expressions, I've been trying and with them and it means manually updating the expression when adding urls etc. which is not what I've looking for, plus it doesn't work as javascript does not support negative lookbehinds.</p>