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Marc-André Bombeck
fea1d1e0b5
Output of `node scripts/strip-planning-tags.mjs --write`: 3,157 comment lines in 1,308 files lose the work-item identifier at their head. Release versions and issue references stay; nothing outside comment text changes, which the script checks per file against a comment-free printout. healthlog/no-planning-tags is enabled at error level with this commit, so the tree it lands on is clean.
77 lines
3.1 KiB
TypeScript
77 lines
3.1 KiB
TypeScript
/**
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* Window-trend helpers for the health-chart `showTrend` overlay.
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*
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* Two complementary deltas:
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*
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* - `weeklyDelta` — first vs last regression-line value, normalised
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* to a per-week rate. Stable for short windows
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* (≤ 90 days) where the user is asking "what is
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* this metric doing this week / month".
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* - `splitHalfDelta` — mean of the second half minus mean of the first
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* half of the visible series. Stays meaningful
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* for long ("All") ranges where the per-week rate
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* rounds to ±0 in the 1-decimal formatter.
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*
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* v1.4.16 — the maintainer reported the chart trend overlay reads
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* "+0.0 kg/Woche" on the All filter, even when their weight clearly
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* shifted across years. Root cause: `weeklyDelta = (last − first) / days
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* × 7` is mathematically correct but visually rounds to zero whenever
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* the slope-per-day is small enough that 7× still falls below the
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* formatter's display precision. The split-half delta side-steps the
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* rounding entirely because it doesn't divide by the window width.
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*
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* Pure & deterministic — pinned by unit test.
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*/
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export interface WindowTrendInput {
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/** Sorted ascending by timestamp. */
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rawValues: number[];
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/** Sorted ascending by timestamp. Must align 1:1 with `rawValues`. */
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trendValues: number[];
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/** Days between the first and last point of the visible series. */
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windowDays: number;
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}
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export interface WindowTrendResult {
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/** Linear-trend per-week delta. Always present when ≥ 2 points. */
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weeklyDelta: number;
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/**
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* First-half-mean vs second-half-mean delta of the raw (not trend)
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* values. Reported as `null` for short windows or when one of the
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* halves is empty (n < 2 split into two halves).
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*/
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splitHalfDelta: number | null;
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}
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/** Default threshold above which the split-half delta is computed. */
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export const SPLIT_HALF_THRESHOLD_DAYS = 90;
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export function computeWindowTrend(
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input: WindowTrendInput,
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splitHalfThresholdDays = SPLIT_HALF_THRESHOLD_DAYS,
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): WindowTrendResult | null {
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if (input.rawValues.length < 2) return null;
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if (input.trendValues.length !== input.rawValues.length) return null;
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if (!Number.isFinite(input.windowDays) || input.windowDays <= 0) return null;
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const firstTrend = input.trendValues[0];
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const lastTrend = input.trendValues[input.trendValues.length - 1];
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const weeklyDelta = ((lastTrend - firstTrend) / input.windowDays) * 7;
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let splitHalfDelta: number | null = null;
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if (input.windowDays >= splitHalfThresholdDays) {
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const mid = Math.floor(input.rawValues.length / 2);
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const firstHalf = input.rawValues.slice(0, mid);
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const secondHalf = input.rawValues.slice(mid);
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if (firstHalf.length > 0 && secondHalf.length > 0) {
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const meanFirst =
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firstHalf.reduce((sum, value) => sum + value, 0) / firstHalf.length;
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const meanSecond =
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secondHalf.reduce((sum, value) => sum + value, 0) / secondHalf.length;
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splitHalfDelta = meanSecond - meanFirst;
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}
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}
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return { weeklyDelta, splitHalfDelta };
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}
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