lexicographical_order 1.5.0

A string generator that helps to implement real-time editing of an ordered sequence. this makes reordering transactions faster and simpler.

About

A string generator designed to enhance real-time editing of ordered sequences by making the process of reordering, sorting, and interleaving transactions more efficient.

Usage

• between(String prev, String next).
  It generates a lexicographically ordered string between prev and next. The returned string is intended to be used as a sort key for some data.

  final mid = between(prev: 'B', next: 'D');
  assert(
    areEqual(
      [mid, 'D', 'B']..sort(),
      ['B', mid, 'D'],
    ),
  );
  

• generateOrderKeys(int keyCount).
  It generates a series of strings to serve as sorting keys for data.

  final keyCount = 100; 
  final orderKeys = generateOrderKeys(keyCount);
  

  Use cases:

  1. When 'between' is unsuitable due to an empty table or collection:

     Future<void> addTodo(CreateTodo command) async {
       final String orderKey = todos.isEmpty 
         ? generateOrderKeys(1).first // <==
         : between(prev: todos.last.orderKey);
            
       final todo = await todoRepository.create(command, orderKey);
       todos.add(todo);
     }
     

  2. During migration to an efficient ordered system:

     Future<void> migrateToLexicalOrderSystem(Table table) async {
       final itemCount = table.count();
       final orderKeys = generateOrderKeys(itemCount);
       /* omitted */
     }