Project drawer state is restored upon refresh

spec/extensions/tree-view-spec.coffee

@@ -9,7 +9,9 @@ describe "TreeView", ->
   beforeEach ->
     rootView = new RootView(pathToOpen: require.resolve('fixtures/'))
     project = rootView.project
-    treeView = new TreeView(rootView)
+
+    rootView.registerExtension(TreeView)
+    treeView = rootView.find(".tree-view").view()
     treeView.root = treeView.find('> li:first').view()
     sampleJs = treeView.find('.file:contains(sample.js)')
     sampleTxt = treeView.find('.file:contains(sample.txt)')
@@ -38,6 +40,24 @@ describe "TreeView", ->
       expect(rootEntries.find('> .file:contains(sample.js)')).toExist()
       expect(rootEntries.find('> .file:contains(sample.txt)')).toExist()
 
+  describe "serialization", ->
+    newTreeView = null
+
+    afterEach ->
+      newTreeView.deactivate()
+
+    it "restores expanded directories and selected file when deserialized", ->
+      treeView.find('.directory:contains(zed)').click()
+      sampleJs.click()
+      newRootView = RootView.deserialize(rootView.serialize())
+      newRootView.registerExtension(TreeView)
+
+      newTreeView = newRootView.find(".tree-view").view()
+
+      expect(newTreeView).toExist()
+      expect(newTreeView.selectedEntry()).toMatchSelector(".file:contains(sample.js)")
+      expect(newTreeView.find(".directory:contains(zed)")).toHaveClass("expanded")
+
   describe "when a directory's disclosure arrow is clicked", ->
     it "expands / collapses the associated directory", ->
       subdir = treeView.root.find('.entries > li:contains(dir/)').view()

spec/spec-helper.coffee

@@ -19,7 +19,6 @@ afterEach ->
   document.title = defaultTitle
   ensureNoDirectorySubscriptions()
 
-
 window.keymap.bindKeys '*', 'meta-w': 'close'
 $(document).on 'close', -> window.close()
 

src/extensions/tree-view/tree-view.coffee

@@ -9,14 +9,31 @@ _ = require 'underscore'
 
 module.exports =
 class TreeView extends View
-  @activate: (rootView) ->
+  @activate: (rootView, state) ->
     requireStylesheet 'tree-view.css'
-    rootView.horizontal.prepend(new TreeView(rootView))
+
+    if state
+      @treeView = TreeView.deserialize(state, rootView)
+    else
+      @treeView = new TreeView(rootView)
+
+    rootView.horizontal.prepend(@treeView)
 
   @content: (rootView) ->
     @div class: 'tree-view', tabindex: -1, =>
       @subview 'root', new DirectoryView(directory: rootView.project.getRootDirectory(), isExpanded: true)
 
+  @deserialize: (state, rootView) ->
+    treeView = new TreeView(rootView)
+    treeView.root.deserializeEntryExpansionStates(state.directoryExpansionStates)
+    treeView.selectEntryForPath(state.selectedPath)
+    treeView
+
+  @serialize: ->
+    @treeView.serialize()
+
+  root: null
+
   initialize: (@rootView) ->
     @on 'click', '.entry', (e) =>
       entry = $(e.currentTarget).view()
@@ -37,15 +54,23 @@ class TreeView extends View
     @on 'tree-view:unfocus', => @rootView.activeEditor()?.focus()
     @rootView.on 'tree-view:focus', => this.focus()
 
+  serialize: ->
+    directoryExpansionStates: @root.serializeEntryExpansionStates()
+    selectedPath: @selectedEntry()?.getPath()
+
   deactivate: ->
     @root.unwatchEntries()
 
   selectActiveFile: ->
     activeFilePath = @rootView.activeEditor()?.buffer.path
-    for element in @find(".file")
-      fileView = $(element).view()
-      if fileView.getPath() == activeFilePath
-        @selectEntry(fileView)
+    @selectEntryForPath(activeFilePath)
+
+  selectEntryForPath: (path) ->
+    for element in @find(".entry")
+      view = $(element).view()
+      if view.getPath() == path
+        @selectEntry(view)
+        return
 
   moveDown: ->
     selectedEntry = @selectedEntry()