Redux learning notes 04 -- using multiple reducers to manage data

Program shop 2021-05-03 11:25:56
redux learning notes using multiple


Write it at the front

As our systems get more and more complex , Use one Reducer Function to manage global data , Will make a Reducer Functions get bloated , Not conducive to the later development and management .

For example, a library application system , We need to manage book data , Librarian data , Reader data , Borrowing record data, purchasing data, etc . If you put the data in one Reducer in , Then it will cause data management confusion , It is not conducive to the later maintenance and development .

A better solution is : Create multiple Reducer, They are used to manage books , Administrators , Readers and other data . When we need to update book data , Just look at the management book Reducer The code can be , No need to care about other Reducer. This saves time and effort , There are ways to reduce the amount of bug.

Now let's introduce an example of how to create multiple Reducer, That is, how to split the big Reducer.

Suppose the business scenario

For example, we are now going to develop a library application , We need to manage the librarians and administrators in the library .

Book data management requirements are as follows : View book list , Add new books to the book list , Remove books from the list of books .

Administrator data management requirements are as follows : Set the administrator's name , Role and other information

With this simple business scenario , We start to set the corresponding Redux Set it up .

Create the first one reducer, Managing librarian data

First we need to create a few action tye Constant , newly build UserType.js file , The code is as follows :

export const SET_FIRST_NAME = "SET_FIRST_NAME";
export const SET_LAST_NAME = "SET_LAST_NAME";
export const ADD_NEW_USER_ROLE = "ADD_NEW_USER_ROLE";
export const REMOVE_USER_ROLE = "REMOVE_USER_ROLE";
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After the creation is finished , Use these constants to define action, Used to call reducer Logic in . newly build UserAction.js file , The code is as follows :

import { SET_FIRST_NAME, SET_LAST_NAME, ADD_NEW_USER_ROLE, REMOVE_USER_ROLE } from "./UserType"
export const setFirstName = firstName => {
return {
type: SET_FIRST_NAME,
payload: firstName
}
}
export const setLastName = lastName => {
return {
type: SET_LAST_NAME,
payload: lastName
}
}
export const addNewUserRole = newUserRole => {
return {
type: ADD_NEW_USER_ROLE,
payload: newUserRole
}
}
export const removeUserRole = roleName => {
return {
type: REMOVE_USER_ROLE,
payload: roleName
}
}
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Finally, by definition reducer function , Used to correspond action Action in , newly build UserReducer.js file , The code is as follows :

// Define the original user data ,reducer The purpose of this is to modify the data , And then return the data 
const initialUserState = {
firstName: "",
lastName: "",
userRoleList: []
}
// introduce type Constant ,reducer Received in action Data sent , stay reducer Medium judgement type type , To deal with 
import { SET_FIRST_NAME, SET_LAST_NAME, ADD_NEW_USER_ROLE, REMOVE_USER_ROLE } from "./UserType"
const UserReducer = (state = initialUserState, action) => {
switch(action.type) {
case SET_FIRST_NAME:
return {
...state,
firstName: action.payload
}
case SET_LAST_NAME:
return {
...state,
lastName: action.payload
}
case ADD_NEW_USER_ROLE:
let newUserRoleList = [...state.userRoleList]
if (!newUserRoleList.includes(action.payload)) {
newUserRoleList.push(action.payload)
}
return {
...state,
userRoleList: newUserRoleList
}
case REMOVE_USER_ROLE:
return {
...state,
userRoleList: state.userRoleList.filter(roleName => roleName !== action.payload)
}
default:
return state;
}
}
export default UserReducer;
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Create a second reducer, Managing the data of books

Empathy , First new BookType.js file , Definition type Constant .

export const ADD_NEW_BOOK = "ADD_NEW_BOOK";
export const REMOVE_NEW_BOOK = "REMOVE_NEW_BOOK";
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Then use these constants to define action, newly build BookAction.js file , The code is as follows :

import { ADD_NEW_BOOK, REMOVE_NEW_BOOK } from "./BookType";
export const addNewBooks = newBookName => {
return {
type: ADD_NEW_BOOK,
payload: newBookName
}
}
export const removeNewBooks = bookName => {
return {
type: REMOVE_NEW_BOOK,
payload: newBookName
}
}
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The final definition reducer, Manage book information , newly build BookReducer.js file , The code is as follows :

const initialBookState = {
bookList: [" Things of the Ming dynasty ", " Water margin "]
}
import { ADD_NEW_BOOK, REMOVE_NEW_BOOK } from "./BookType";
const BookReducer = (state = initialBookState, action) => {
if (action.type === ADD_NEW_BOOK) {
return {
...initialBookState,
bookList: [...initialBookState.bookList, action.payload]
}
}
if (action.type === REMOVE_NEW_BOOK) {
return {
...initialBookState,
bookList: initialBookState.bookList.filter(_book => _book !== action.payload)
}
}
return state;
}
export default BookReducer;
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Merge two reducer, establish reducer store example

Now we've created two reducer, The next thing we need to do is to put these two reducer combined , Create a redux store example . I need to use redux Provided by the package combineReducers Method , newly build Store.js file , The specific code is as follows :

// Lead-in required redux Method 
import { createStore, combineReducers } from 'redux'
// Introduce a defined reducer
import BookReducer from './BookReducer'
import UserReducer from './UserReducer';
// Use this method to merge two reducer
const rootReducer = combineReducers({
BookReducer,
UserReducer
});
// Use the merged reducer establish store example 
const Store = createStore(rootReducer)
export default Store;
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The use of multiple reducer Created store example , What's the data structure like

Now we have created reduxe example , You can get... In a component redux Data in , Take a look at the data structure at this time , The component code is as follows :

import React from 'react'
import Store from 'myRedux/Store'
class Login extends React.Component {
constructor(props) {
super(props);
this.state = {
}
}
componentDidMount() {
this.setState((preState, props) => ({
...preState,
...Store.getState()
}));
Store.subscribe(() => {
// Print out redux Data in 
console.log("Redux data: ", Store.getState());
this.setState((preState, props) => ({
...preState,
...Store.getState()
}));
});
}
render() {
return (
<div>
The test page
</div>
);
}
}
export default Login;
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In the console , We can see redux The data structure in is as follows :

{
"UserReducer": {
"firstName": "",
"lastName": "",
"userRoleList": []
},
"BookReducer": {
"bookList": [
" Things of the Ming dynasty ",
" Water margin "
]
}
}
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understand redux Data structure of , When we get this data later , So we won't make a mistake .

How to modify one of them reducer Managed data

Now the data has , We also need to be able to modify multiple reducer The data of , It's very simple . Although we define two reducer, But it's totally a reducer, Follow this process when modifying data : introduce action, Then the trigger action. For example, the following code example :

import React from 'react';
import Store from "myRedux/Store";
// introduce action
import { setFirstName, setLastName } from "myRedux/UserAction";
const LeftSideBar = () => {
const modifyUserName = () => {
// Trigger action
Store.dispatch(setFirstName("Allen"));
Store.dispatch(setLastName("Feng"));
}
return (
<div>
<button className="icon" onClick={modifyUserName} ></button>
</div>
);
}
export default LeftSideBar;
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At the end

How to create multiple reducer To manage redux data , This is what I learned . In some big projects , Create multiple reduxer It can help us to manage clearly redux Data in , I hope you can try this .

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https://qdmana.com/2021/05/20210503112203916Y.html

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