Meta+ and meta- change the editor font size

spec/app/root-view-spec.coffee

@@ -409,3 +409,14 @@ describe "RootView", ->
       rootView.editors()[0].remove()
       expect(document.title).toBe rootView.project.getPath()
 
+  describe "font size adjustment", ->
+    it "increases/decreases font size when increase/decrease-font-size events are triggered", ->
+      fontSizeBefore = rootView.getFontSize()
+      rootView.trigger 'increase-font-size'
+      expect(rootView.getFontSize()).toBe fontSizeBefore + 1
+      rootView.trigger 'increase-font-size'
+      expect(rootView.getFontSize()).toBe fontSizeBefore + 2
+      rootView.trigger 'decrease-font-size'
+      expect(rootView.getFontSize()).toBe fontSizeBefore + 1
+      rootView.trigger 'decrease-font-size'
+      expect(rootView.getFontSize()).toBe fontSizeBefore

src/app/keymaps/editor.coffee

@@ -2,6 +2,8 @@ window.keymap.bindKeys '*'
   'meta-s': 'save'
   'meta-w': 'close'
   'alt-meta-i': 'show-console'
+  'meta-+': 'increase-font-size'
+  'meta--': 'decrease-font-size'
 
   right: 'move-right'
   left: 'move-left'

src/app/root-view.coffee

@@ -28,7 +28,7 @@ class RootView extends View
 
   extensions: null
   extensionStates: null
-  fontSize: null
+  fontSize: 18
 
   initialize: ({ pathToOpen }) ->
     @extensions = {}
@@ -57,6 +57,9 @@ class RootView extends View
       @project.setPath(path) unless @project.getRootDirectory()
       @setTitle(path)
 
+    @on 'increase-font-size', => @setFontSize(@getFontSize() + 1)
+    @on 'decrease-font-size', => @setFontSize(@getFontSize() - 1)
+
   afterAttach: (onDom) ->
     @focus() if onDom