Helper is not scoped to request, but to app

[bengourley]

The helpers compactJsHtml() and compactJs() are attached to app.helpers, which means that they exist for the duration of the application, not the request (as expected).

Here is a problem that is causes:

app.js

app.get('/', routes.index); // No JS on page
app.get('/edit', compact.js(['edit']), routes.edit); // `edit` JS on the page

layout.jade (inherited by index and edit views)

//...
if (compactJsHtml !== 'undefined')
  !=compactJsHtml()
//...

• If you view / then the page is output as desired: no JS.
• If you view /edit then the page is output as desired: edit JS
• Subsequent views to / output the edit JS because compactJsHtml is still defined from the request to
  /edit