title: express route, check if req.params parameter is empty
body: <p>I'm new to node and express and I would appreciate any help. I'm trying to write a get request which checks if the req.params.address_line is empty and does something if it is, but can't seem to figure out how to do that. So far I have tried this:</p>
  
  <pre><code>app.get('/smth/smth_else/:address_line', function(req, res){
    if(req.params.address_line===""){
      res.send("Hello World.")
    }
  }
  </code></pre>
  
  <p>This isn't working though so I don't think it is correct. How can I check if the address_line is empty? I googled it extensively, but can't find a working solution. Thanks!</p>