             vEncoding ?= 'utf8'
             @encoding = vEncoding
           else
-            @encoding = null
+            @encoding = undefined
           @_contents = @_loadContentSync(aOptions)
         else
           ### !pragma coverage-skip-next ###

            vEncoding ?= 'utf8'
            @encoding = vEncoding
          else
            @encoding = null
          @_contents = result
          @skipSize = aOptions.skipSize if @skipSize isnt aOptions.skipSize
        done(err, result)

          vEncoding ?= 'utf8'
          @encoding = vEncoding
        else
          @encoding = undefined
        @skipSize = aOptions.skipSize if @skipSize isnt aOptions.skipSize
        @_contents = result
    else
