Jade - Template Engine: How to check if a variable exists

This should work:

- if (typeof(username) !== 'undefined'){  //-do something-}

node.js pug express

Simpler than @Chetan's method if you don't mind testing for falsy values instead of undefined values:

if locals.username  p= usernameelse  p No Username!

This works because the somewhat ironically named locals is the root object for the template.

node.js pug express

if 'username' in this    p=username

This works because res.locals is the root object in the template.

CodeHunter