Toggle folding upon 'mousedown' on a foldable line's fold-icon

spec/editor-view-spec.coffee

@@ -715,6 +715,14 @@ describe "EditorView", ->
         expect(selection1.getScreenRange()).toEqual [[4, 10], [5, 27]]
         expect(selection2.getScreenRange()).toEqual [[6, 10], [8, 27]]
 
+    describe "mousedown on the fold icon of a foldable line number", ->
+      it "toggles folding on the clicked buffer row", ->
+        expect(editor.isFoldedAtScreenRow(1)).toBe false
+        editorView.gutter.find('.line-number:eq(1) .fold-icon').mousedown()
+        expect(editor.isFoldedAtScreenRow(1)).toBe true
+        editorView.gutter.find('.line-number:eq(1) .fold-icon').mousedown()
+        expect(editor.isFoldedAtScreenRow(1)).toBe false
+
   describe "when text input events are triggered on the hidden input element", ->
     it "inserts the typed character at the cursor position, both in the buffer and the pre element", ->
       editorView.attachToDom()

src/editor-view.coffee

@@ -348,6 +348,11 @@ class EditorView extends View
       @editor.destroyFoldWithId(id)
       false
 
+    @gutter.on 'mousedown', '.foldable .fold-icon', (e) =>
+      bufferRow = $(e.target).parent().data('bufferRow')
+      @editor.toggleFoldAtBufferRow(bufferRow)
+      return false
+
     @renderedLines.on 'mousedown', (e) =>
       clickCount = e.originalEvent.detail
 

src/editor.coffee

@@ -598,6 +598,14 @@ class Editor extends Model
     for row in [bufferRange.start.row..bufferRange.end.row]
       @destroyFoldsContainingBufferRow(row)
 
+  # Public: Folds the given buffer row if it's not currently folded, and unfolds
+  # it otherwise.
+  toggleFoldAtBufferRow: (bufferRow) ->
+    if @isFoldedAtBufferRow(bufferRow)
+      @unfoldBufferRow(bufferRow)
+    else
+      @foldBufferRow(bufferRow)
+
   # Public: Returns whether the current row is folded.
   isFoldedAtCursorRow: ->
     @isFoldedAtScreenRow(@getCursorScreenRow())