The Reducers

🔄 Reducers – Pure State Updates

A reducer is a pure function that updates a specific part of the state in response to an action.

✨ Key Principles

Reducers:

• Take the current state and an action
• Return a new state
• Must be pure — no side effects, service calls, or randomness
• Are called after effects, if any exist

🚫 Async Tips

Reducers may return Task<TState>, but should avoid unnecessary await.

IncrementReducer.cs

internal class IncrementReducer : IReducer<CounterState, IncrementCounterResultAction>
{
    public Task<CounterState> ReduceAsync(CounterState state, IncrementCounterResultAction action)
    => Task.FromResult(state with
    {
        Count = action.Count
    });
}