UnityECS/LocalPackages/com.nimin.tinyecs/Runtime/ComponentId.cs

using Unity.Burst;

namespace GameCore.TinyECS
{
    internal static class ComponentIdHelper
    {
        public static int currentId;
    }
    
    public struct ComponentId<T>
    {
        public int id;
        public static readonly SharedStatic<ComponentId<T>> Instance = SharedStatic<ComponentId<T>>.GetOrCreate<ComponentId<T>>();

        [BurstDiscard]
        static void EnsureInitialized()
        {
            if (Instance.Data.id == 0)
            {
                Instance.Data.id = ++ComponentIdHelper.currentId;
            }
        }

        public static int Get()
        {
            EnsureInitialized();
            return Instance.Data.id;
        }
    }
}