Merge pull request #205 from sideshowbarker/vim9script-support

Add Vim9Script support

Author: mattn

autoload/vimlparser.vim

@@ -352,7 +352,7 @@ function s:JavascriptCompiler.compile_let(node)
       call self.out('%s.prototype.%s %s %s;', klass, name, op, right)
       return
     endif
-    if left =~ '\.' || op != '='
+    if left =~ '[\.\[]' || op != '='
       call self.out('%s %s %s;', left, op, right)
     else
       call self.out('var %s %s %s;', left, op, right)