React-Redux每当我尝试从购物车中删除商品时，都会抛出“发货不是函数”

如何解决React-Redux每当我尝试从购物车中删除商品时，都会抛出“发货不是函数”

在购物车部分的产品上单击“-”按钮，将通过“ onDecreaseCountClicked”道具调用removeItemFromCart（）。 removeItemFromCart（），调用dispatch（）和getState（），但返回错误“ getState不是函数”。不太确定这里是什么问题...

动作

import shop from '../api/shop'
import * as types from '../constants/ActionTypes'

const receiveProducts = products => ({
  type: types.RECEIVE_PRODUCTS,products
})

export const getAllProducts = () => dispatch => {
  shop.getProducts(products => {
    dispatch(receiveProducts(products))
  })
}

const addToCartUnsafe = productId => ({
  type: types.ADD_TO_CART,productId
})

export const addToCart = productId => (dispatch,getState) => {
 if (getState().products.byId[productId].inventory > 0) {
    dispatch(addToCartUnsafe(productId))
  }
}

const removeFromCartUnsafe = productId => ({
  type: types.DELETE_SINGLE_ITEM,productId
})

export const removeItemFromCart = productId => (dispatch,getState) => {
  if (getState().products.byId[productId].inventory > 0) {
    dispatch(removeFromCartUnsafe(productId))
  }
}


 export const checkout = products => (dispatch,getState) => {
  const { cart } = getState()

  dispatch({
   type: types.CHECKOUT_REQUEST
  })
  shop.buyProducts(products,() => {
    dispatch({
      type: types.CHECKOUT_SUCCESS,cart
    })
  })
}

App.js

import React from 'react'
import ProductsContainer from './ProductsContainer'
import CartContainer from './CartContainer'

const App = () => (
  <div>
    <h2>Shopping Cart Example</h2>
    <hr/>
    <ProductsContainer />
    <hr/>
    <CartContainer />
  </div>
)

export default App

CartContainer.js

import React from 'react'
import PropTypes from 'prop-types'
import { connect } from 'react-redux'
import { checkout } from '../actions'
import { getTotal,getCartProducts } from '../reducers'
import Cart from '../components/Cart'

const CartContainer = ({ products,total,checkout}) => (
  <Cart
    products={products}
    total={total}
    onCheckoutClicked={() => checkout(products)} 
    />
)

CartContainer.propTypes = {
  products: PropTypes.arrayOf(PropTypes.shape({
    id: PropTypes.number.isRequired,title: PropTypes.string.isRequired,price: PropTypes.number.isRequired,quantity: PropTypes.number.isRequired
  })).isRequired,total: PropTypes.string,checkout: PropTypes.func.isRequired
}

const mapStateToProps = (state) => ({
  products: getCartProducts(state),total: getTotal(state)
})

export default connect(
  mapStateToProps,{ checkout }
)(CartContainer)

Cart.js

import React from 'react'
import PropTypes from 'prop-types'
import Product from './Product'
import {removeItemFromCart} from '../actions/index'

 const Cart  = ({ products,onCheckoutClicked }) => {
  const hasProducts = products.length > 0
  const nodes = hasProducts ? (
    products.map(product =>
      <>
      <Product
        title={product.title}
        price={product.price}
        quantity={product.quantity}
        key={product.id}
        onDecreaseCountClicked={() => removeItemFromCart(product.id)}
      />
      <input type='number' value={product.quantity.toString()}/>
      </>
    )
  ) : (
    <em>Please add some products to cart.</em>
  )

  return (
    <div>
      <h3>Your Cart</h3>
      <div>{nodes}</div>
      <p>Total: &#36;{total}</p>
      <button onClick={onCheckoutClicked}
        disabled={hasProducts ? '' : 'disabled'}>
        Checkout
      </button>
    </div>
  )
}

Cart.propTypes = {
  products: PropTypes.array,onCheckoutClicked: PropTypes.func
}

export default Cart

Product.js

import React from 'react'
import PropTypes from 'prop-types'

const Product = ({ price,quantity,title,onDecreaseCountClicked,key }) => (
  <div>
    {title} - &#36;{price}{quantity ? ` x ${quantity}` : null}
    {onDecreaseCountClicked && <button onClick={onDecreaseCountClicked()}>-</button>}
  </div>
)

Product.propTypes = {
  price: PropTypes.number,quantity: PropTypes.number,title: PropTypes.string
}

export default Product