I've been using Repl.it to work with Phaser, but I'm looking into offline app versions that might run faster. However, I've tried Atom, Brackets, and VS Code, and they all seem to be unable to debug the files the same way that Repl.it does. I'm getting error messages such as "unexpected reserved word" or "expected an identifier and instead saw 'class'" that I wouldn't normally see when I run my code on Repl.it, while the debugger doesn't show the errors I actually want to see that are present. Is there something I'm doing wrong that is causing these problems?

Here's an example set of files. Code Sandbox works as well, but it is also fully browser-based. Could you let me know how to run these files with an offline code editor app?