为什么我的 React redux 状态不会导致重新渲染？

Question

你好，我有一个问题，当我尝试使用选择器时，我的 redux 状态没有导致重新渲染。我对 react-redux 和打字稿还很陌生。我一直在尝试 google 这个，大多数互联网线程都说这是因为你需要创建一个新对象 return 让 redux 知道状态已经改变。我已经在做了。但是我的对象没有重新渲染，状态已更新但没有导致重新渲染。

我做错了什么？

我的 Redux reducer


import { Computer, GraphicsCard } from "../../interfaces";

const initialState: Computer = {
    graphicsCard: null,
}


interface SelectGraphicsCardAction {
    type: "SELECT_GRAPHICSCARD";
    payload: GraphicsCard;
}

interface UnselectGraphicsCardAction {
    type: "UNSELECT_GRAPHICSCARD";
}


export type Action = SelectGraphicsCardAction | UnselectGraphicsCardAction

export const computerReducer = (state = initialState, action: Action) => {
    switch(action.type){
        case "SELECT_GRAPHICSCARD": {
            const { payload } = action;
            console.log(state, payload)

           const newState = {
                ...state,
                graphicsCard: {
                    ...state.graphicsCard,
                    ...payload
                }
            }
            //This evaluates to false
            console.log(state === newState)

            return newState
        }
        case "UNSELECT_GRAPHICSCARD": {
            return {
                ...state,
                graphicsCard: null
            }
        }
        default:
            return state;
    }

}

我的 Redux 商店

import { configureStore } from '@reduxjs/toolkit'
import { computerReducer } from './reducers/ComputerReducer'
// ...

 export const store = configureStore({
  reducer: {
    computer: computerReducer
  },
})

我selecting/using这里的状态。

function SelectedComputer() {
  const computer = useSelector((state: Computer) => state);
  const dispatch = useDispatch();
  const { graphicsCard } = computer;

  //Logging correct state
  console.log(computer)

  return (
    <div className="fixed top-10 right-4 bg-white rounded-t-lg">
      <p className="text-center font-bold border-b-1 border-b-black bg-gray-100 rounded-t-lg shadow-md">
        Selected Parts
      </p>
      <div className="flex flex-row">
        <CpuFill className="m-1" />
        {graphicsCard ? (
          //Not rendering this when updating state.
          <p>{graphicsCard.name}</p>
        ) : (
          <p>No Graphicscard selected!</p>
        )}
        <Trash className="flex justify-center"/>
      </div>

编辑：这是一个使用 dispatch 来更新状态的片段。

import React, { FC } from "react";
import { Button, Card } from "react-bootstrap";
import { useDispatch } from "react-redux";
import { Component, ComputerComponent } from "../interfaces";
import { Action } from "../redux/reducers/ComputerReducer";

interface ComponentCard {
  component: Component;
  buttonText: string;
  type: string;
}

interface DomainImage {
  [key: string]: string;
}

const ComponentCard: FC<ComponentCard> = ({ component, buttonText, type }) => {
  const dispatch = useDispatch();

  const imageMap: DomainImage = {
    "inet.se": "https://cdn.inet.se/gfx/ext/226/brand-assets/inet-logo2.jpg",
    "komplett.se":
      "https://cached-images.bonnier.news/gcs/di-bilder-prod/mly/fcb28d10-158c-485b-814c-b461baa0e188.jpeg",
    "webhallen.se":
      "https://static.wikia.nocookie.net/logopedia/images/6/65/Webhallen_2021.svg/revision/latest?cb=20220420201224",
  };

  return (
    <Card className="flex flex-row items-center w-50 shadow-md mt-2 mb-2">
      <div className="flex justify-center items-center mr-3">
        <img className="h-36 w-40 p-2" src={component.imgUrl} />
      </div>
      <div className="flex-1 text-left">
        <h4 className="text-base">{component.name}</h4>
        <p>
          <span>
            ArtNr: {component.articleNumber}, Manufacturer:{" "}
            {component.manufacturer}
          </span>
        </p>
        <h4 className="absolute right-36 top-10">
          <span>{component.price} :-</span>
        </h4>
      </div>
        <Button
          color=""
          className="absolute right-5 h-10 w-20"
          onClick={() => dispatch({ type, payload: component })}
        >
          {buttonText}
        </Button>
        <a href={component.url} target="_blank" className="absolute right-5 bottom-0">
          <img
            className="w-15 h-10"
            src={imageMap[component.domainName]}
            alt={component.name}
          />
        </a>
    </Card>
  );
};

Answer 1

就其价值而言，您在这里使用的是一种极其过时（2019 年之前）的 Redux 风格，它最终将是您使用现代 Redux 编写的代码的 4 倍左右——尤其是与 TypeScript 结合使用时。

我强烈建议您遵循 official Redux tutorial and the TypeScript QuickStart，它会向您显示您必须设置的所有其他类型（它比您现在拥有的要少很多）。

你的问题的根源可能是意外的状态修改，这也可能发生在遗留 Redux 中的 reducer 之外 - 在现代 Redux 中，你会在你进行突变的时候立即得到一个错误 - 节省你的时间调试。所以我真的建议你切换过来，你可能会摆脱这个错误。

为什么我的 React redux 状态不会导致重新渲染？

Why is my react redux state not causing a re-render?

reactjs

typescript

redux

react-redux

state