Ask HN: How do you maintain JavaScript web apps?

Lets say I have a large code base built using React and other needed libraries. I have different repositories based on the functional breakdown. Each repo has its own package.json. With the way dependent packages release newer versions, its really hard to maintain dependent packages in turn resulting in audit issues and adding newer functionalities. Also, updating newer versions of React becomes a pain. So how do you all maintain javascript webapps? Any best practices or pointers to follow.