For supplemental curriculum, it will be up to you to make it through this self-paced curriculum and lean on instructors for support. This is designed to help you get to the same "Order Of Growth" as your classmates. You're encouraged to pair program together through these challenges, which will help ensure you're clear on the concepts presented.
Start by doing Khan Academy's Intro to Programming. Start with the "Drawing Basics" unit, and continue to the end. This should give you a good review of the fundamental syntax available in JavaScript. For additional review in structuring programs and problem solving, go through the advanced Javascript course. If you get through all of that and still feel like you can't make it through the Node.js curriculum, take a look at the Advanced JS Natrual Simulations course.
You will know you're ready to move on when you can complete any Code Wars katas marked 8 or 7.