Add View#observeConfig as a space-pen extension

src/app/config.coffee

@@ -50,11 +50,14 @@ class Config
   observe: (keyPathString, callback) ->
     keyPath = keyPathString.split('.')
     value = @valueAtKeyPath(keyPath)
-    @on 'update', =>
+    updateCallback = =>
       newValue = @valueAtKeyPath(keyPath)
       unless newValue == value
         value = newValue
         callback(value)
+    subscription = { destroy: => @off 'update', updateCallback  }
+    @on 'update', updateCallback
     callback(value)
+    subscription
 
 _.extend Config.prototype, EventEmitter

src/app/window.coffee

@@ -13,6 +13,7 @@ RootView = require 'root-view'
 Pasteboard = require 'pasteboard'
 require 'jquery-extensions'
 require 'underscore-extensions'
+require 'space-pen-extensions'
 
 windowAdditions =
   rootViewParentSelector: 'body'

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

@@ -65,7 +65,7 @@ class TreeView extends ScrollView
     @rootView.command 'tree-view:reveal-active-file', => @revealActiveFile()
     @rootView.on 'active-editor-path-change', => @selectActiveFile()
     @rootView.project.on 'path-change', => @updateRoot()
-    config.observe 'core.hideGitIgnoredFiles', => @updateRoot()
+    @observeConfig 'core.hideGitIgnoredFiles', => @updateRoot()
 
     @selectEntry(@root) if @root
 

src/stdlib/space-pen-extensions.coffee

@@ -0,0 +1,19 @@
+_ = require 'underscore'
+{View} = require 'space-pen'
+
+originalRemove = View.prototype.remove
+
+_.extend View.prototype,
+  observeConfig: (keyPath, callback) ->
+    @subscribe(config.observe(keyPath, callback))
+
+  subscribe: (subscription) ->
+    @subscriptions ?= []
+    @subscriptions.push(subscription)
+
+  unsubscribe: ->
+    subscription.destroy() for subscription in @subscriptions ? []
+
+  remove: (args...) ->
+    @unsubscribe()
+    originalRemove.apply(this, args)