native‑feeling swipe back/forward for all touch devices

app/javascript/controllers/swipe_nav_controller.js

@@ -0,0 +1,93 @@
+import { Controller } from "@hotwired/stimulus"
+
+const SWIPE_DISTANCE_PX = 60
+const SWIPE_AXIS_RATIO = 1.2
+const SWIPE_TIME_MS = 700
+
+export default class extends Controller {
+  connect() {
+    this.onPointerDown = this.onPointerDown.bind(this)
+    this.onPointerMove = this.onPointerMove.bind(this)
+    this.onPointerUp = this.onPointerUp.bind(this)
+    window.addEventListener("pointerdown", this.onPointerDown, { passive: true })
+  }
+
+  disconnect() {
+    window.removeEventListener("pointerdown", this.onPointerDown, { passive: true })
+    this.detachTrackingListeners()
+  }
+
+  onPointerDown(event) {
+    if (!event.isPrimary) return
+    if (event.pointerType !== "touch" && event.pointerType !== "pen") return
+    if (event.button && event.button !== 0) return
+    if (this.shouldIgnoreTarget(event.target)) return
+
+    this.tracking = true
+    this.pointerId = event.pointerId
+    this.startX = event.clientX
+    this.startY = event.clientY
+    this.startTime = performance.now()
+    this.lastX = event.clientX
+    this.lastY = event.clientY
+
+    window.addEventListener("pointermove", this.onPointerMove, { passive: true })
+    window.addEventListener("pointerup", this.onPointerUp, { passive: true })
+    window.addEventListener("pointercancel", this.onPointerUp, { passive: true })
+  }
+
+  onPointerMove(event) {
+    if (!this.tracking || event.pointerId !== this.pointerId) return
+    this.lastX = event.clientX
+    this.lastY = event.clientY
+  }
+
+  onPointerUp(event) {
+    if (!this.tracking || event.pointerId !== this.pointerId) return
+
+    const elapsed = performance.now() - this.startTime
+    const deltaX = this.lastX - this.startX
+    const deltaY = this.lastY - this.startY
+
+    this.tracking = false
+    this.pointerId = null
+    this.detachTrackingListeners()
+
+    if (elapsed > SWIPE_TIME_MS) return
+    if (Math.abs(deltaX) < SWIPE_DISTANCE_PX) return
+    if (Math.abs(deltaX) < Math.abs(deltaY) * SWIPE_AXIS_RATIO) return
+
+    if (deltaX > 0) {
+      window.history.back()
+    } else {
+      window.history.forward()
+    }
+  }
+
+  detachTrackingListeners() {
+    window.removeEventListener("pointermove", this.onPointerMove, { passive: true })
+    window.removeEventListener("pointerup", this.onPointerUp, { passive: true })
+    window.removeEventListener("pointercancel", this.onPointerUp, { passive: true })
+  }
+
+  shouldIgnoreTarget(target) {
+    if (!target) return true
+    if (target.closest("input, textarea, select, [contenteditable='true']")) return true
+    if (this.isInHorizontalScrollableArea(target)) return true
+    return false
+  }
+
+  isInHorizontalScrollableArea(target) {
+    let el = target
+    while (el && el !== document.body) {
+      const style = window.getComputedStyle(el)
+      const overflowX = style.overflowX
+      if ((overflowX === "auto" || overflowX === "scroll" || overflowX === "overlay") &&
+          el.scrollWidth > el.clientWidth + 1) {
+        return true
+      }
+      el = el.parentElement
+    }
+    return false
+  }
+}

app/views/layouts/application.html.slim

@@ -37,7 +37,7 @@ html data-theme="light"
     - if ENV["UMAMI_WEBSITE_ID"].present?
       - umami_host = ENV["UMAMI_HOST"].presence || "https://umami.hackorum.dev"
       script[async defer data-website-id=ENV["UMAMI_WEBSITE_ID"] src="#{umami_host}/script.js"]
-  body class=(content_for?(:sidebar) ? "has-sidebar" : nil) data-controller="sidebar"
+  body class=(content_for?(:sidebar) ? "has-sidebar" : nil) data-controller="sidebar swipe-nav"
     - if user_signed_in? && current_user.username.blank?
       .global-warning
         span Please set a username in Settings.