Greetings, everyone!
I’ve created a little script, which will allow you to export all your contracts, transactions and scripts in a form of a ZIP file. It will also inherit contract name if it was deployed before export.
In order to use it, you will need to open dev tools and paste following code into the console and then press enter to execute it:
var script = document.createElement("script");
document.body.appendChild(script);
script.src = "https://maxstalker.github.io/flow-playground-scripts/export-files.js";
It will pull a javascript file hosted on GitHub, which will do all the dirty work for you 
You can take a look at source files and instructions here: