Ask HN: How to write a web app that will outlast the latest JS trends?

HN is rife with JS framework wars, comparisons, latest feature news, libraries of the week, etc. What are surefire strategies for building a web app that won't have to be completely rewritten in 2-3 years? If I choose to write a web app in AngularJS and then in 2 years the Web community decides to coalesce around the new latest and greatest framework, technology, then it seems like I'll be in a rut.

How do you write a modern web app and be sure it will still be maintainable in the 2-3 year time frame?