title: How to set a HTTP Header Key/Value Pair within the MEAN Stack
body: <p>I'm using the MEAN stack and need to set a HTTP header key/value pair within   my web app.</p>
  
  <p>i.e. <code>my_key: my_value</code></p>
  
  <p>Using Angular 5 and found the following code:</p>
  
  <pre><code>app.use('/api', function (req, res) {
     let url = config.API_HOST + req.ur
      req.headers['someHeader'] = 'someValue'
      req.pipe(request(url)).pipe(res)
  })
  </code></pre>
  
  <p>but unsure how to apply to my requirement as I believe the only line that I need from the above code is:</p>
  
  <pre><code>req.headers['my_key'] = 'my_value'
  </code></pre>
  
  <p>but not sure if I need the <code>req.pipe</code> line.</p>