ux fix on product increase

resources/js/checkout/bbk-cart-controller.js

@@ -18,6 +18,7 @@ export default class extends Controller {
     connect() {
         this.onChanged = this.onChanged.bind(this)
         this.onKeydown = this.onKeydown.bind(this)
+        this.updateTimers = new Map() // line id -> pending debounce timer
 
         window.addEventListener('bbk-cart:changed', this.onChanged)
         window.addEventListener('bbk-cart:open', this.open.bind(this))
@@ -30,6 +31,7 @@ export default class extends Controller {
     disconnect() {
         window.removeEventListener('bbk-cart:changed', this.onChanged)
         document.removeEventListener('keydown', this.onKeydown)
+        this.updateTimers.forEach((timer) => clearTimeout(timer))
     }
 
     onChanged(event) {
@@ -63,7 +65,11 @@ export default class extends Controller {
     submit(event) {
         event.preventDefault()
         const form = event.target.closest('form')
-        if (form) this.send(form)
+        if (!form) return
+
+        // A remove is a deliberate, one-shot action — only the quantity form
+        // (typing, or the +/- stepper below) benefits from debouncing.
+        form.classList.contains('bbk-cart-qty') ? this.scheduleSend(form) : this.send(form)
     }
 
     // +/- stepper buttons inside a line
@@ -73,7 +79,22 @@ export default class extends Controller {
         const input = form.querySelector('input[type="number"]')
         const next = Math.max(0, parseInt(input.value || '0', 10) + Number(event.params.dir))
         input.value = String(next)
-        this.send(form)
+        this.scheduleSend(form)
+    }
+
+    // Repeated clicks (or spinner nudges) update the input instantly but only
+    // send once they settle for 300ms — sending on every single click was
+    // firing overlapping requests that raced each other and made the drawer
+    // visibly flicker/lag under quick clicking.
+    scheduleSend(form) {
+        const lineId = form.closest('[data-bbk-line-id]')?.dataset.bbkLineId
+        if (!lineId) return this.send(form)
+
+        clearTimeout(this.updateTimers.get(lineId))
+        this.updateTimers.set(lineId, setTimeout(() => {
+            this.updateTimers.delete(lineId)
+            this.send(form)
+        }, 300))
     }
 
     async send(form) {