Make undo grouping interval configurable

spec/text-editor-component-spec.coffee

@@ -1925,14 +1925,26 @@ describe "TextEditorComponent", ->
       expect(editor.lineTextForBufferRow(0)).toBe 'var quicksort = function () {'
 
     it "groups events that occur close together in time into single undo entries", ->
+      currentTime = 0
+      spyOn(Date, 'now').andCallFake -> currentTime
+
+      atom.config.set('editor.undoGroupingInterval', 100)
+
       editor.setText("")
       componentNode.dispatchEvent(buildTextInputEvent(data: 'x', target: inputNode))
-      componentNode.dispatchEvent(buildTextInputEvent(data: 'y', target: inputNode))
-      componentNode.dispatchEvent(buildTextInputEvent(data: 'z', target: inputNode))
 
+      currentTime += 99
+      componentNode.dispatchEvent(buildTextInputEvent(data: 'y', target: inputNode))
+
+      currentTime += 99
       componentNode.dispatchEvent(new CustomEvent('editor:duplicate-lines', bubbles: true, cancelable: true))
 
-      expect(editor.getText()).toBe "xyz\nxyz"
+      currentTime += 100
+      componentNode.dispatchEvent(new CustomEvent('editor:duplicate-lines', bubbles: true, cancelable: true))
+      expect(editor.getText()).toBe "xy\nxy\nxy"
+
+      componentNode.dispatchEvent(new CustomEvent('core:undo', bubbles: true, cancelable: true))
+      expect(editor.getText()).toBe "xy\nxy"
 
       componentNode.dispatchEvent(new CustomEvent('core:undo', bubbles: true, cancelable: true))
       expect(editor.getText()).toBe ""

src/config-schema.coffee

@@ -105,6 +105,11 @@ module.exports =
       scrollPastEnd:
         type: 'boolean'
         default: false
+      undoGroupingInterval:
+        type: 'integer'
+        default: 500
+        minimum: 0
+        description: 'Time interval in milliseconds within which operations will be grouped in the undo history'
       useHardwareAcceleration:
         type: 'boolean'
         default: true

src/text-editor-component.coffee

@@ -21,7 +21,6 @@ TextEditorComponent = React.createClass
 
   statics:
     performSyncUpdates: false
-    groupingInterval: 500
 
   visible: false
   autoHeight: false
@@ -458,7 +457,7 @@ TextEditorComponent = React.createClass
     selectedLength = inputNode.selectionEnd - inputNode.selectionStart
     editor.selectLeft() if selectedLength is 1
 
-    insertedRange = editor.transact @constructor.groupingInterval, ->
+    insertedRange = editor.transact atom.config.get('editor.undoGroupingInterval'), ->
       editor.insertText(event.data)
     inputNode.value = event.data if insertedRange
 

src/text-editor-element.coffee

@@ -150,7 +150,7 @@ stopEventPropagationAndGroupUndo = (commandListeners) ->
       newCommandListeners[commandName] = (event) ->
         event.stopPropagation()
         model = @getModel()
-        model.transact TextEditorComponent.groupingInterval, ->
+        model.transact atom.config.get('editor.undoGroupingInterval'), ->
           commandListener.call(model, event)
   newCommandListeners