title: Express: how the app.set('view engine','ejs') executed innerly?
body: <p>So I know the method app.set() is that setting value for a name. therefore, app.get() could get the value by name. but accordingly, if I set 'view engine' to 'ejs',where is the app.get('view engine')? if not have, how dose the app.set('view engine','ejs') work?</p>
  
  <p>thank you for responding this wizard question.</p>