add-sequential

name	add-sequential
description	Add sequential queue processing to ensure Cubit method calls execute one after another in order

Add Sequential Queue Processing

This skill queues Cubit method calls and processes them one after another in order.

What This Skill Does

Adds the sequential parameter to a mix() call so that:

• Method calls are queued instead of running concurrently
• Each call waits for the previous one to complete
• All calls execute in the order they were made

Instructions

Step 1: Identify the Method

Ask the user which Cubit method needs sequential processing, or identify methods that:

• Must execute in order (messages, transactions)
• Should not run concurrently (database writes)
• Every call matters and must complete

Step 2: Add Sequential

Add sequential: sequential to the mix() call:

import 'package:bloc_superpowers/bloc_superpowers.dart';

class ChatCubit extends Cubit<ChatState> {
  ChatCubit() : super(const ChatState());

  void sendMessage(String text) => mix(
    key: this,
    sequential: sequential,  // Add this line
    () async {
      final message = await api.sendMessage(text);
      emit(state.copyWith(
        messages: [...state.messages, message],
      ));
    },
  );
}

Step 3: Understand the Behavior

With sequential:

• First call: Executes immediately
• Second call while first is running: Queued, waits for first to complete
• Third call: Queued behind second
• All calls execute in order, one at a time

// User sends 3 messages rapidly
cubit.sendMessage('Hello');    // Executes immediately
cubit.sendMessage('How');      // Queued (waits for first)
cubit.sendMessage('Are you?'); // Queued (waits for second)
// Result: Messages sent in order: "Hello", "How", "Are you?"