Add autoWidth to TextEditor

spec/text-editor-spec.coffee

@@ -5516,6 +5516,14 @@ describe "TextEditor", ->
       editor.update({autoHeight: true})
       expect(editor.getAutoHeight()).toBe(true)
 
+  describe "auto width", ->
+    it "returns false by default but can be customized", ->
+      expect(editor.getAutoWidth()).toBe(false)
+      editor.update({autoWidth: true})
+      expect(editor.getAutoWidth()).toBe(true)
+      editor.update({autoWidth: false})
+      expect(editor.getAutoWidth()).toBe(false)
+
   describe '.get/setPlaceholderText()', ->
     it 'can be created with placeholderText', ->
       newEditor = atom.workspace.buildTextEditor(

src/text-editor-presenter.coffee

@@ -896,6 +896,9 @@ class TextEditorPresenter
       @updateScrollHeight()
       @updateEndRow()
 
+  didChangeAutoWidth: ->
+    @emitDidUpdateState()
+
   setContentFrameWidth: (contentFrameWidth) ->
     if @contentFrameWidth isnt contentFrameWidth or @editorWidthInChars?
       oldContentFrameWidth = @contentFrameWidth

src/text-editor.coffee

@@ -127,7 +127,7 @@ class TextEditor extends Model
       @softTabs, @firstVisibleScreenRow, @firstVisibleScreenColumn, initialLine, initialColumn, tabLength,
       @softWrapped, @decorationManager, @selectionsMarkerLayer, @buffer, suppressCursorCreation,
       @mini, @placeholderText, lineNumberGutterVisible, @largeFileMode, @clipboard,
-      @assert, grammar, @showInvisibles, @autoHeight, @scrollPastEnd, @editorWidthInChars,
+      @assert, grammar, @showInvisibles, @autoHeight, @autoWidth, @scrollPastEnd, @editorWidthInChars,
       @tokenizedBuffer, @displayLayer, @invisibles, @showIndentGuide, @softWrapHangingIndentLength,
       @softWrapped, @softWrapAtPreferredLineLength, @preferredLineLength
     } = params
@@ -144,6 +144,7 @@ class TextEditor extends Model
     @selections = []
     @hasTerminatedPendingState = false
 
+    @autoWidth ?= false
     @autoHeight ?= true
     @mini ?= false
     @scrollPastEnd ?= true
@@ -320,6 +321,10 @@ class TextEditor extends Model
             @autoHeight = value
             @editorElement?.didChangeAutoHeight()
 
+        when 'autoWidth'
+          if value isnt @autoWidth
+            @autoWidth = value
+            @presenter?.didChangeAutoWidth()
         else
           throw new TypeError("Invalid TextEditor parameter: '#{param}'")
 
@@ -3552,6 +3557,9 @@ class TextEditor extends Model
     Grim.deprecate("This is now a view method. Call TextEditorElement::getWidth instead.")
     @width
 
+  getAutoWidth: ->
+    @autoWidth
+
   # Experimental: Scroll the editor such that the given screen row is at the
   # top of the visible area.
   setFirstVisibleScreenRow: (screenRow, fromView) ->