PageUp/PgDn/Home/End navigation; fix rename API path; immediate local rename update

2026-05-03 22:58:51 +00:00
parent 48d7435d0b
commit c3146744b7
6 changed files with 381 additions and 178 deletions
@@ -0,0 +1,124 @@
+type ScrollOptions = {
+  topPad?: number
+  bottomPad?: number
+  keyboardWindowMs?: number
+  getScrollContainer?: () => HTMLElement | null
+}
+
+export function createKeyboardFollowScroll(options: ScrollOptions = {}) {
+  const {
+    topPad = 84,
+    bottomPad = 84,
+    keyboardWindowMs = 260,
+    getScrollContainer = () =>
+      (document.querySelector('main') as HTMLElement | null) ?? document.documentElement
+  } = options
+
+  let scrollAnimationFrame: number | null = null
+  let scrollTargetY: number | null = null
+  let scrollVelocity = 0
+  let keyboardFollowUntil = 0
+
+  const markKeyboardFollow = () => {
+    keyboardFollowUntil = performance.now() + keyboardWindowMs
+  }
+
+  const keyboardFollowActive = () => performance.now() < keyboardFollowUntil
+
+  const clampScrollY = (y: number, scroller: HTMLElement) => {
+    const maxY = Math.max(0, scroller.scrollHeight - scroller.clientHeight)
+    return Math.min(maxY, Math.max(0, y))
+  }
+
+  const cursorScrollTarget = (el: HTMLElement): number | null => {
+    const scroller = getScrollContainer() ?? document.documentElement
+    const rect = el.getBoundingClientRect()
+    const scrollerRect = scroller.getBoundingClientRect()
+    const visibleTop = scrollerRect.top + topPad
+    const visibleBottom = scrollerRect.bottom - bottomPad
+
+    if (rect.top >= visibleTop && rect.bottom <= visibleBottom) return null
+
+    if (rect.top < visibleTop) {
+      return clampScrollY(scroller.scrollTop + (rect.top - visibleTop), scroller)
+    }
+
+    return clampScrollY(scroller.scrollTop + (rect.bottom - visibleBottom), scroller)
+  }
+
+  const runSmoothCursorScroll = () => {
+    if (scrollAnimationFrame != null) return
+
+    const step = () => {
+      const scroller = getScrollContainer() ?? document.documentElement
+
+      if (scrollTargetY == null) {
+        scrollVelocity *= 0.68
+        if (Math.abs(scrollVelocity) > 0.05) {
+          const next = clampScrollY(scroller.scrollTop + scrollVelocity, scroller)
+          scroller.scrollTop = next
+          scrollAnimationFrame = requestAnimationFrame(step)
+          return
+        }
+        scrollVelocity = 0
+        scrollAnimationFrame = null
+        return
+      }
+
+      const current = scroller.scrollTop
+      const delta = scrollTargetY - current
+      const absDelta = Math.abs(delta)
+      if (absDelta < 0.6 && Math.abs(scrollVelocity) < 0.08) {
+        scroller.scrollTop = scrollTargetY
+        scrollVelocity = 0
+        scrollTargetY = null
+        scrollAnimationFrame = null
+        return
+      }
+
+      const stiffness = Math.min(0.022, 0.01 + absDelta / 10000)
+      const damping = 0.76
+      scrollVelocity += delta * stiffness
+      scrollVelocity *= damping
+
+      const next = clampScrollY(current + scrollVelocity, scroller)
+      if (next === current) scrollVelocity = 0
+      scroller.scrollTop = next
+      scrollAnimationFrame = requestAnimationFrame(step)
+    }
+
+    scrollAnimationFrame = requestAnimationFrame(step)
+  }
+
+  const keepVisible = (el: HTMLElement | null) => {
+    if (!keyboardFollowActive()) {
+      scrollTargetY = null
+      scrollVelocity = 0
+      return
+    }
+
+    if (!el) {
+      scrollTargetY = null
+      return
+    }
+
+    const target = cursorScrollTarget(el)
+    if (target == null) {
+      scrollTargetY = null
+      return
+    }
+
+    scrollTargetY = target
+    runSmoothCursorScroll()
+  }
+
+  const cancel = () => {
+    if (scrollAnimationFrame != null) cancelAnimationFrame(scrollAnimationFrame)
+    scrollAnimationFrame = null
+    scrollTargetY = null
+    scrollVelocity = 0
+    keyboardFollowUntil = 0
+  }
+
+  return { markKeyboardFollow, keepVisible, cancel }
+}