fixing es6 code

[leandrozuliani]

I've fixed some bugs in example codes from readme.md file

[ghost]

Hi @leandrozuliani, I'm your friendly neighborhood Microsoft Open Technologies, Inc. Pull Request Bot (You can call me MSOTBOT). Thanks for your contribution!

This seems like a small (but important) contribution, so no Contribution License Agreement is required at this point. Real humans will now evaluate your PR.

TTYL, MSOTBOT;