Coding Volunteer Website

Hey all- I'd like to gain more coding experience through creating real world projects, but am having trouble getting started on my own.

I'm very much an "on the job" type of learner- so I think I could learn best working beside someone else to create a project, but in my current position I don't have anyone else around me interested in coding or who is experienced in coding.

My question is- does anyone know of a website that will allow me to volunteer as a coding assistant or apprentice? I'd like the ability to join a real world project with a senior developer, have that SD give me tasks to complete- and if I run into trouble, they can give me tips?

I'd specifically like to do this with full-stack Javascript.

Thanks for your time!