CartReducer.js

import { createSlice } from "@reduxjs/toolkit";

export const CartSlice = createSlice({
  name: "cart",
  initialState: {
    cart: [],
  },
  reducers: {
    addToCart: (state, action) => {
      //if this statement is true, then the item is already in the cart
      const itemPresent = state.cart.find(
        (item) => item.id === action.payload.id
      );
      if (itemPresent) {
        itemPresent.quantity++;
      } else {
        state.cart.push({ ...action.payload, quantity: 1 });
      }
    },
    removeFromCart: (state, action) => {
      const removeItem = state.cart.filter(
        (item) => item.id !== action.payload.id
      );
      state.cart = removeItem;
    },
    incrementQuantity: (state, action) => {
      const itemPresent = state.cart.find(
        (item) => item.id === action.payload.id
      );
      itemPresent.quantity++;
    },
    decrementQuantity: (state, action) => {
        const itemPresent = state.cart.find(
          (item) => item.id === action.payload.id
        );
        if(itemPresent.quantity == 1){
            itemPresent.quantity = 0;
            const removeItem = state.cart.filter(
              (item) => item.id !== action.payload.id
            );
            state.cart = removeItem;
        }
        else{
            itemPresent.quantity--;
        }
    },

    cleanCart: (state)=>{
      state.cart = [];
    }
  },
});

export const {addToCart, removeFromCart, incrementQuantity, decrementQuantity, cleanCart} = CartSlice.actions;

export default CartSlice.reducer;