3 Level Menu Items

[vinaypoddar]

• I'm submitting a ...
  [ ] feature request

• What is the current behavior?
  I really appreciate your module and it is very helpful but it would be more appreciated if you can make it compatible to more sub levels like 3-4.

• What is the motivation / use case for changing the behavior?
  As of now I am trying to develop somthing which have menu depth till 3-4 and your module only takes care of menu items till 2 levels.

• Please tell us about your environment:

• Angular version: 4.4.4
• Browser: [all ]

• Other information (e.g. detailed explanation, stacktraces, related issues, suggestions how to fix, links for us to have context, eg. stackoverflow, gitter, etc)
  So, what I feel as a fix we just need to add the below code spnippet in your slidemenu.template.html
  I made a sample but i am not able to push the branch for pull request