Što pruža Redux Toolkit (RTK) u odnosu na klasični Redux?

Question

Accepted Answer

**Redux Toolkit (RTK)** je službeni, preporučeni način pisanja Redux-a danas. Eliminiše poznati boilerplate klasičnog Redux-a — ručne tipove akcija, kreatere akcija, logiku nepromenljive ažuriranja, postavljanje store-a — dok čuvaju iste osnovne principe.

## Problem boilerplate-a koji RTK rešava

```js
// ❌ classic Redux — verbose: action types, creators, switch reducers, manual immutability
const INCREMENT = "counter/increment";
const increment = () => ({ type: INCREMENT });
function reducer(state = { value: 0 }, action) {
  switch (action.type) {
    case INCREMENT: return { ...state, value: state.value + 1 };
    default: return state;
  }
}
```

## RTK: createSlice radi sve

```js
import { createSlice, configureStore } from "@reduxjs/toolkit";

export const { increment, incrementBy } = counterSlice.actions; // action creators AUTO-generated
const store = configureStore({ reducer: { counter: counterSlice.reducer } });
```

`createSlice` automatski generiše tipove akcija i kreatere, i — preko **Immer** — vam omogućava pisanje "mutativnog" reducer koda koji je sigurno konvertovan u nepromenljiva ažuriranja. Jedan sažet slice zamenjuje sve ručne delove.

## Šta drugog RTK uključuje

```text
configureStore   → store setup with DevTools + thunk middleware preconfigured
createAsyncThunk → standard async (pending/fulfilled/rejected actions) for data fetching
createEntityAdapter → normalized state + CRUD reducers for collections
RTK Query        → a full data-fetching/caching layer (like React Query, built into Redux)
```

## Primer createAsyncThunk

```js
export const fetchUsers = createAsyncThunk("users/fetch", () => api.getUsers());
// auto-dispatches users/fetch/pending | fulfilled | rejected — handle in extraReducers
```

## Zašto je RTK sada standard

```text
✓ ~75% less code than classic Redux
✓ Immer → no manual immutable spread logic (fewer bugs)
✓ Good defaults (DevTools, thunk) out of the box
✓ Encourages best practices (slices, normalized data)
✓ RTK Query bundles server-state management
```

## Zašto je to važno

Najveća kritika klasičnog Redux-a bila je njegov boilerplate; RTK direktno rešava taj problem, što je razlog zašto je to sada **zvanična preporuka** i šta "korišćenje Redux-a" znači u modernim codebase-ima.

Razumevanje `createSlice` (powered by Immer, automatski generisane akcije), `createAsyncThunk` (asinkrono), `createEntityAdapter` (normalizacija) i RTK Query (stanje servera) je neophodno za savremeni Redux rad — čuva Redux-ovu predvidljivost dok uklanja ceremoniju koja je terala mnoge timove ka alternativama.