Editing Openai/696e35f8-9d68-8009-a35a-26169c8ccbe9 (section)

==== 2. Client-side Action Queue (Serialized Mutations) ====

Complexity: ⭐⭐
When to use: Most CRUD apps with optimistic UX

===== Core idea =====
* All user actions become commands.
* Commands are applied optimistically.
* Commands are queued and sent to the server in order.
* Next command waits until previous one resolves.

===== API calls =====

Same endpoints as before, but:
* Only one in-flight mutation at a time.
* Requests are sent sequentially.

===== Example flow =====
# User creates todo → optimistic add → enqueue CreateTodo
# User edits that todo → optimistic edit → enqueue EditTodo(temp-id)
# Server responds with real ID → client rewrites queued commands to use real ID
# Next command is sent

===== How it handles fast user edits =====
* Editing a not-yet-created todo works because: - The edit command waits behind the create command. - IDs are rewritten when create resolves.
* Reorder is queued behind prior mutations, ensuring server state matches expectations.

===== Trade-offs =====
* Slightly higher latency for later actions
* Requires command queue + ID remapping
* Still assumes server success (rollback logic is basic)

✅ Huge reliability gain for modest complexity