React Pro - Real World App - Ch8. 03 - Typed State

// src/pages/cms/products/CMSProductsPage.tsx
import { Product } from '@/model/product';
import { get } from '@/services/products/products.api';
import { useReducer } from "react"

// NEW
export type ProductsState = {
  products: Product[];
  pending: boolean;
}

// NEW
function productsReducer(state: ProductsState, action: any) {
  switch (action.type) {
    case 'pending':
      return { ...state, pending: action.payload };
    case 'productsGetSuccess':
      return { pending: false, products: action.payload}
  }
  return state;
}

export const initialState = { pending: false, products: [] };

export function CMSProductsPage() {
  const [state, dispatch] = useReducer(productsReducer, initialState);

  async function getProductsHandler() {
    dispatch({ type: 'pending', payload: true } );
    const res = await get();
    dispatch({ type: 'productsGetSuccess', payload: res.items})
  }

  return (
    <div>
      <h1 className="title">CMS</h1>

      Pagina Prodotti

      <hr className="my-8"/>

      {state.pending && <div>loading...</div>}

      <button className="btn primary" onClick={getProductsHandler}>GET</button>

      <pre>{JSON.stringify(state, null, 2)}</pre>
    </div>
  )
}