Mithril.js: Investigate duplicated DOM tree issue in routed mount point

[pygy]

@modmanx reported a problem where he ends up with a duplicated DOM tree when switching routes:

https://gitter.im/lhorie/mithril.js?at=58e4abacad849bcf425273df

hi, I updated to version 1.1.1 and when I change routes from route2 to route1 and back to route2 main layout is in DOM twice

{
   "/": {
       render: function() {
           return m(PageChooseEvent)
       },
   },
   "/:id_event/brackets": {
       render: function() {
         appstate.active_page = 'brackets'
           return m(Layout, m(PageBrackets))
       },
   }
}

m("div.page--event", ...) is what Layout component returns

@modmanx it would be nice if you could provide a JSBin repro. Also, what version were you upgrading from?

[modmanx]

Hi,
I'll try to make JSBin repro now. I believe it has something to do because I'm using iframe with youtube embed and enablejsapi parameter set to one.

[pygy]

@modmanx thanks for the follow up :-)

[modmanx]

Hello again. I found out what do I need to do to fix this but not sure where exactly is the problem. I can not reproduce on jsbin or locally. I will try to copy project and remove as much code to reproduce bug.

Anyhow - All I did was to include app.js code (generated code with webpack) to be last script to be included in body.

[pygy]

:+1:

What version were you upgrading from?

[modmanx]

Now I'm rethinking and I believe we did not had this code exactly in a state that would cause bug like it's happening now, so I don't think that's bug related. It was 1.0.1 before. I will copy code and set mithril to this version and check if bug is there. Gimme a minute.