JavaScript has HTML5 IndexedDB, available to it out of the box.
As for SQLite, you can use it provided that you first port it as a WinRT component that can be used from JavaScript, for example. using C ++ / CX. Its API surface is not so big, so it is certainly possible. I experimented with compiling SQLite for Metro some time ago, and there were only a few Win32 API calls that were not available in the application container and had to be replaced - nothing serious.
Pavel minaev
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