Optimistic Updates & Background Tasks
New decorators for instant UI feedback and non-blocking handlers.
Shopping Cart
@optimisticJIT compute
Subtotal, tax, and total are derived in get_context_data() (JIT pattern). "Add Item" uses @optimistic for instant client-side feedback before the server responds.
| Item | Price | Qty | Line Total | |
|---|---|---|---|---|
| Wireless Keyboard | $79.99 | $79.99 | ||
| USB-C Hub | $49.99 | $49.99 | ||
| Monitor Stand | $34.99 | $34.99 |
Order Summary
Items4
Subtotal$214.96
Tax (8%)$17.20
Total$232.16
Actions
@optimistic@background
"Add Item" uses @optimistic for instant UI feedback. "Check Inventory" uses @background for non-blocking async.
Decorator Reference
views.pypython
from djust.decorators import optimistic, background, event_handler
class CartView(LiveView):
def get_context_data(self, **kwargs):
# JIT pattern: compute derived values at render time
subtotal = sum(i["price"] * i["qty"] for i in self.items)
return {"subtotal": subtotal, "tax": round(subtotal * 0.08, 2)}
@event_handler()
@optimistic # Instant client-side feedback before server confirms
def add_item(self, **kwargs):
self.items.append({"name": "New", "price": 19.99, "qty": 1})
@event_handler()
@background # Runs without blocking — UI stays responsive
def check_inventory(self, **kwargs):
time.sleep(2) # Simulate slow API call
self.inventory_status = "All items in stock!"