Have you looked into using IndexedDB? It's pretty widely supported [1] and far more performant than Files API last time I used it intensively (few years ago).

Have you looked into using IndexedDB? It's pretty widely supported [1] and far more performant than Files API last time I used it intensively (few years ago). [1]: http://caniuse.com/#feat=indexeddb http://caniuse.com/#feat=indexeddb