There's really only one thing that will doom the codebase, and that is neglect. As you know, there is an abundance of tools and libraries out there, especially in the JavaScript community. Sometimes you're locked into using older versions for any number of reasons, some internal. Ultimately the most important thing you can do is remain attentive to how the codebase is growing and take any and all opportunities to prune and shape the plants in the garden. There's endless work to be done. Don't push back against the urge to nurture. As with life, code can only grow better and more workable with positive attention.