App Onmount - Expressjs

<h3 id='app.onmount'>app.on('mount', callback(parent))</h3>

The mount event is fired on a sub-app, when it is mounted on a parent app. The parent app is passed to the callback function.

<div class="doc-box doc-info" markdown="1"> **NOTE**

Sub-apps will:

Not inherit the value of settings that have a default value. You must set the value in the sub-app.
Inherit the value of settings with no default value.

For details, see Application settings.

</div>

var admin = express()

admin.on('mount', function (parent) {
  console.log('Admin Mounted')
  console.log(parent) // refers to the parent app
})

admin.get('/', function (req, res) {
  res.send('Admin Homepage')
})

app.use('/admin', admin)