Browser support
Modern browsers get instant navigation; older ones fall back to a normal MPA, automatically.
Sparke runs on modern browsers with fetch,
DOMParser, the History API and
CustomEvent – which is essentially every browser
shipping today.
Older browsers
Anywhere those APIs are missing, Sparke quietly does nothing and the site behaves as a normal multi-page website. There is no error and no broken state – that's the whole point of progressive enhancement.
Because the no-JS and old-browser paths are just your ordinary server-rendered pages, you never have to test a separate “degraded” experience – it's the same HTML.
Footprint
The minified library is about 14.5 KB – roughly 5 KB gzipped or 4.6 KB brotli – with zero dependencies.