ES6 Features - Use cases for Proxy
I strongly recommend that you follow along the blog post and look at the examples one by one.
You should use a recent browser, preferably Chrome.
Some examples require that the code is running on a webserver and not opened from the filesystem. You can use the simple http-server npm module for that. Just start serving and navigate to http://localhost:8080.
If you don't want to bother hosting it for yourself, you can use our GitHub-hosted page instead.