From https://once.com/writebook

app/javascript/controllers/toc_view_controller.js

@@ -0,0 +1,23 @@
+import { Controller } from "@hotwired/stimulus"
+import { readCookie, setCookie } from "helpers/cookie_helpers"
+
+export default class extends Controller {
+  static targets = [ "switch" ]
+  static values = { id: String }
+
+  connect() {
+    this.#restoreViewPref(this.idValue)
+  }
+
+  saveViewPref(event) {
+    const viewType = event.target.dataset.tocViewTypeValue
+    setCookie(this.idValue, viewType)
+  }
+
+  #restoreViewPref(id) {
+    const viewType = readCookie(id) || "grid"
+    this.switchTargets.forEach(switchTarget => {
+      switchTarget.checked = switchTarget.dataset.tocViewTypeValue === viewType
+    }
+  )}
+}