A great amount of time in software development is spent searching for libraries and reading their docs, to avoid reinventing the wheel each time you are doing something pretty common ('saving a file').
Polyfill and shim libraries are making the lives of developers so much easier. The problem is usually to know about them.
One year ago, I remember searching for Blob and File saving shims, without much success. Thus my fascination, by randomly bumping into what seems great ones.
It does make the 'first webapp' very small, which is quite elegant.