web/flows: resize captcha iframes

web/src/elements/utils/listenerController.ts

@@ -0,0 +1,41 @@
+// This is a more modern way to handle disconnecting listeners on demand.
+
+// example usage:
+
+/*
+export class MyElement extends LitElement {
+
+   this.listenerController = new ListenerController();
+
+   connectedCallback() {
+      super.connectedCallback();
+      window.addEventListener("event-1", handler1, { signal: this.listenerController.signal });
+      window.addEventListener("event-2", handler2, { signal: this.listenerController.signal });
+      window.addEventListener("event-3", handler3, { signal: this.listenerController.signal });
+   }
+
+   disconnectedCallback() {
+      // This will disconnect *all* the event listeners at once, and resets the listenerController,
+      // releasing the memory used for the signal as well. No more trying to map all the
+      // `addEventListener` to `removeEventListener` tediousness!
+      this.listenerController.abort();
+      super.disconnectedCallback();
+   }
+}
+*/
+
+export class ListenerController {
+    listenerController?: AbortController;
+
+    get signal() {
+        if (!this.listenerController) {
+            this.listenerController = new AbortController();
+        }
+        return this.listenerController.signal;
+    }
+
+    abort() {
+        this.listenerController?.abort();
+        this.listenerController = undefined;
+    }
+}