app.js carried the whole SVG chart implementation (~380 lines: palette,
percentile fans, the shared line-series renderer, per-metric wrappers,
pointer hover) alongside its page logic. That moves to chart.js: the
drawing dimensions live there as live-bound module state behind
setChartWidth(); attachChartHover takes the day list as a parameter
instead of reaching into page globals. app.js keeps buildChart and the
PNG export — page orchestration — and drops to ~500 lines. Any page can
now plot a metric series (e.g. a history sparkline on the day page).
calendar.js's hand-rolled streaming loader — bounded-parallel pool,
token cancellation, stale-while-revalidate re-merge — becomes
cache.js chunkedFetch(urls, {ttl, concurrency, isCurrent, onResult});
fetchCalendar keeps only its intent (chunk URLs, day merge, contiguous-
prefix rendering). Same pool semantics, verbatim.
Verified: node --check; 108 backend tests; headless-Chromium smoke on
all five pages against live data (chart renders + metric toggle,
calendar grid streams + metric switch, ladders, compare, legend).
The frontend was classic scripts sharing one global scope, with a
load-order contract enforced only by comments (leaflet -> nav ->
shared -> mappicker -> page) and hand-rolled window.Thermograph /
window.LocationPicker namespaces. Page scripts now import what they use;
the dependency graph replaces the ordering contract, and no app globals
remain (Leaflet stays a classic script / global L, loaded first).
nav.js had grown four concerns; it's now three single-purpose modules:
- nav.js: last-location memory + header view-links + locHash.
- units.js: the °F/°C toggle and unit-aware formatting. The compare
special case is gone — pages that want the toggle import units.js;
compare simply doesn't.
- cache.js: the IndexedDB response cache, SWR getJSON, bundle-seeded
view prefetch and neighbor warming. prefetchViews(lat, lon, ownViews)
now takes the calling page's own view names instead of a page-identity
map (VIEW_OWN) — adding a page no longer means editing this module.
The slice->URL map stays here as bundle-contract knowledge.
frontend/package.json ({"type": "module"}) makes CI's node --check
parse the files as modules.
Verified: node --check on all files as modules; 108 backend tests;
headless-Chromium smoke across all five pages against live data — zero
console/page errors, all render assertions pass (cards, chart, calendar
grid + metric switch, ladders, compare ranking, legend scales).
