code: private void addJsString(Node n) {
      String s = n.getString();
      boolean useSlashV = n.getBooleanProp(Node.SLASH_V);
      if (useSlashV) {
        add(jsString(n.getString(), useSlashV));
      } else {
        String cached = escapedJsStrings.get(s);
        if (cached == null) {
          cached = jsString(n.getString(), useSlashV);
          escapedJsStrings.put(s, cached);
        }
        add(cached);
      }
    }
docs: Outputs a JS string, using the optimal (single/double) quote character