From https://once.com/writebook

app/javascript/controllers/copy_to_clipboard_controller.js

@@ -0,0 +1,25 @@
+import { Controller } from "@hotwired/stimulus"
+
+export default class extends Controller {
+  static values = { content: String }
+  static classes = [ "success" ]
+
+  async copy(event) {
+    event.preventDefault()
+    this.reset()
+
+    try {
+      await navigator.clipboard.writeText(this.contentValue)
+      this.element.classList.add(this.successClass)
+    } catch {}
+  }
+
+  reset() {
+    this.element.classList.remove(this.successClass)
+    this.#forceReflow()
+  }
+
+  #forceReflow() {
+    this.element.offsetWidth
+  }
+}