Expanded/collapsed state of directories is preserved when an ancestor is collapsed

src/extensions/tree-view.coffee

@@ -1,5 +1,6 @@
 {View, $$} = require 'space-pen'
 Directory = require 'directory'
+$ = require 'jquery'
 
 module.exports =
 class TreeView extends View
@@ -17,33 +18,55 @@ class DirectoryView extends View
   @content: ({directory, isExpanded}) ->
     @li class: 'directory', =>
       @span '▸', class: 'disclosure-arrow', outlet: 'disclosureArrow', click: 'toggleExpansion'
-      @span directory.getName() + '/', class: 'name'
+      @span directory.getName(), class: 'name'
 
-  initialize: ({@directory, @isExpanded}) ->
-    @expand() if @isExpanded
+  entries: null
+
+  initialize: ({@directory, isExpanded}) ->
+    @expand() if isExpanded
 
   buildEntries: ->
-    contents = $$ -> @ol class: 'entries'
+    @entries = $$ -> @ol class: 'entries'
     for entry in @directory.getEntries()
       if entry instanceof Directory
-        contents.append(new DirectoryView(directory: entry, isExpanded: false))
+        @entries.append(new DirectoryView(directory: entry, isExpanded: false))
       else
-        contents.append $$ -> @li entry.getName(), class: 'file'
-    @append(contents)
+        @entries.append $$ -> @li entry.getName(), class: 'file'
+    @append(@entries)
 
   toggleExpansion: ->
     if @isExpanded then @collapse() else @expand()
 
   expand: ->
+    return if @isExpanded
+    @addClass('expanded')
     @disclosureArrow.text('▾')
     @buildEntries()
+    @deserializeEntries(@entryStates) if @entryStates?
     @isExpanded = true
 
   collapse: ->
+    @entryStates = @serializeEntries()
+    @removeClass('expanded')
     @disclosureArrow.text('▸')
-    @find('.entries').remove()
+    @entries.remove()
+    @entries = null
     @isExpanded = false
 
+  serializeEntries: ->
+    entryStates = {}
+    @entries.find('> .directory.expanded').each ->
+      view = $(this).view()
+      entryStates[view.directory.getName()] = view.serializeEntries()
+    entryStates
+
+  deserializeEntries: (entryStates) ->
+    for directoryName, childEntryStates of entryStates
+      @entries.find("> .directory:contains(#{directoryName})").each ->
+        view = $(this).view()
+        view.entryStates = childEntryStates
+        view.expand()
+