File-extension Questions

I've created my own application in vb.net that saves its documents into a file with it's own custom extension (.eds). assuming that i've

Currently in one of project which is using react on the front-end and ruby on rails on the back-end i can see .js.jsx files for all

I have a file extension checker that i have been working on, and i just cannot figure out why it won't work. i have it testing showing up a

I'm sure this is a simple thing to do but i don't know how. what i want to achieve is something like this: templatefilename = str(