fix #1

[skvggor]

Hi, @heversonr .

First of all, thank you for contributing.

Two things before doing the pull request:

• In this project we use only indentation with tabs and note that used spaces, which we do not use here in .js files.
• In the index.js file, in the lines that 10 and 11, instead of let use const please.

I really enjoyed the help. Thank you very much.

[heversonr]

Ok! I'll push that fix.

[skvggor]

Thanks.