$ npm i
$ node_modules/.bin/gulp serve
This will spin up a local server with livereload.
The version deployed to s3 is minified and compressed to maximize performances. Sometimes (rarely) there are inconsistencies between compressed and uncompressed version. It's a good practice to test the dist build to check that everything is ok.
$ node_modules/.bin/gulp serve:dist
You can now navigate to http://localhost:3000/dist