I like to think of things as lying a spectrum: On one end, you have completely hand-rolled framework-less JavaScript. This requires no learning curve whatsoever, but things may get slow and messy as time progresses and you miss out on the cumulative benefits of a framework. At the other end of the spectrum is something like Ember, which takes a while to learn is is just plain overkill for small projects, but which for big projects starts to pay dividends in the long run.