feat(chart): support fixed y-axis domains

src/components/core/yDomain.ts

@@ -0,0 +1,50 @@
+import type { DisplaySeries, DisplayTrack } from './types'
+
+export type WaveformYDomain = [number, number]
+
+export function normalizeYDomain(
+  domain: readonly [number, number] | undefined,
+): WaveformYDomain | undefined {
+  if (
+    !domain ||
+    !Number.isFinite(domain[0]) ||
+    !Number.isFinite(domain[1]) ||
+    domain[0] === domain[1]
+  ) {
+    return undefined
+  }
+  return domain[0] < domain[1] ? [domain[0], domain[1]] : [domain[1], domain[0]]
+}
+
+export function resolveTrackFixedYDomain(
+  track: Pick<DisplayTrack, 'id'>,
+  yDomains?: Record<string, WaveformYDomain>,
+): WaveformYDomain | undefined {
+  return normalizeYDomain(yDomains?.[track.id])
+}
+
+export function resolveSeriesFixedYDomain(
+  series: Pick<DisplaySeries, 'id'>,
+  yDomain?: WaveformYDomain,
+  yDomains?: Record<string, WaveformYDomain>,
+): WaveformYDomain | undefined {
+  return normalizeYDomain(yDomains?.[series.id]) ?? normalizeYDomain(yDomain)
+}
+
+export function hasFixedYDomainForTrack(
+  track: Pick<DisplayTrack, 'id' | 'visibleSeries'>,
+  yDomain?: WaveformYDomain,
+  yDomains?: Record<string, WaveformYDomain>,
+): boolean {
+  return Boolean(
+    resolveTrackFixedYDomain(track, yDomains) ||
+    track.visibleSeries.some((series) => resolveSeriesFixedYDomain(series, yDomain, yDomains)),
+  )
+}
+
+export function mergeYDomains(domains: readonly WaveformYDomain[]): WaveformYDomain {
+  return [
+    Math.min(...domains.map((domain) => domain[0])),
+    Math.max(...domains.map((domain) => domain[1])),
+  ]
+}