srcmini上一章ReactJS实战教程请查看：React Redux架构基本概念解释
在本节中，我们将学习如何在React应用程序中实现Redux，这里，我们提供了一个连接Redux和React的简单示例。
步骤1：创建react项目
使用create-react-app命令创建一个新的react项目。我们选择项目名称:“reactproject”，现在安装Redux和React-Redux。
$ npx create-react-app reactproject
$ npm install redux react-redux --save 步骤2： 创建文件和文件夹
在此步骤中，我们需要为操作、reducer、组件和容器创建文件夹和文件。创建文件夹和文件后，我们的项目如下图所示。
步骤3：操作action
它使用“type”属性通知应该发送到存储的数据，在这个文件夹中，我们将创建两个文件: index.js和index.spec.js。在这里，我们创建了一个action creator，它返回我们的操作并为每个创建的项设置id。
Index.js
let nextTodoId = 0
export const addTodo = text => ({
type: 'ADD_TODO',
id: nextTodoId++,
text
})
export const setVisibilityFilter = filter => ({
type: 'SET_VISIBILITY_FILTER',
filter
})
export const toggleTodo = id => ({
type: 'TOGGLE_TODO',
id
})
export const VisibilityFilters = {
SHOW_ALL: 'SHOW_ALL',
SHOW_COMPLETED: 'SHOW_COMPLETED',
SHOW_ACTIVE: 'SHOW_ACTIVE'
} Index.spec.js
import * as actions from './index'
describe('todo actions', () => {
it('addTodo should create ADD_TODO action', () => {
expect(actions.addTodo('Use Redux')).toEqual({
type: 'ADD_TODO',
id: 0,
text: 'Use Redux'
})
})
it('setVisibilityFilter should create SET_VISIBILITY_FILTER action', () => {
expect(actions.setVisibilityFilter('active')).toEqual({
type: 'SET_VISIBILITY_FILTER',
filter: 'active'
})
})
it('toggleTodo should create TOGGLE_TODO action', () => {
expect(actions.toggleTodo(1)).toEqual({
type: 'TOGGLE_TODO',
id: 1
})
})
}) 步骤4： reducer
我们知道，动作只会触发应用程序中的更改，而还原器会指定这些更改。reducer是一个函数，它接受两个参数“Action”和“State”来计算和返回一个更新后的状态。它从“操作”读取有效载荷，然后通过相应的状态更新“存储”。
在给定的文件中，每个减速器管理自己的全局状态部分。状态参数对于每个reducer都是不同的，并且对应于它管理的“状态”部分。当应用程序变大时，我们可以将还原器分割成单独的文件，使它们完全独立，并管理不同的数据域。
在这里，我们使用“combineReducers”的辅助功能来添加我们将来可能使用的任何新的reducer。
index.js
import { combineReducers } from 'redux'
import todos from './todos'
import visibilityFilter from './visibilityFilter'
export default combineReducers({
todos,
visibilityFilter
}) Todos.js
const todos = (state = [], action) => {
switch (action.type) {
case 'ADD_TODO':
return [
...state,
{
id: action.id,
text: action.text,
completed: false
}
]
case 'TOGGLE_TODO':
return state.map(todo =>
(todo.id === action.id)
? {...todo, completed: !todo.completed}
: todo
)
default:
return state
}
}
export default todos Todos.spec.js
import todos from './todos'
describe('todos reducer', () => {
it('should handle initial state', () => {
expect(
todos(undefined, {})
).toEqual([])
})
it('should handle ADD_TODO', () => {
expect(
todos([], {
type: 'ADD_TODO',
text: 'Run the tests',
id: 0
})
).toEqual([
{
text: 'Run the tests',
completed: false,
id: 0
}
])
expect(
todos([
{
text: 'Run the tests',
completed: false,
id: 0
}
], {
type: 'ADD_TODO',
text: 'Use Redux',
id: 1
})
).toEqual([
{
text: 'Run the tests',
completed: false,
id: 0
}, {
text: 'Use Redux',
completed: false,
id: 1
}
])
expect(
todos([
{
text: 'Run the tests',
completed: false,
id: 0
}, {
text: 'Use Redux',
completed: false,
id: 1
}
], {
type: 'ADD_TODO',
text: 'Fix the tests',
id: 2
})
).toEqual([
{
text: 'Run the tests',
completed: false,
id: 0
}, {
text: 'Use Redux',
completed: false,
id: 1
}, {
text: 'Fix the tests',
completed: false,
id: 2
}
])
})
it('should handle TOGGLE_TODO', () => {
expect(
todos([
{
text: 'Run the tests',
completed: false,
id: 1
}, {
text: 'Use Redux',
completed: false,
id: 0
}
], {
type: 'TOGGLE_TODO',
id: 1
})
).toEqual([
{
text: 'Run the tests',
completed: true,
id: 1
}, {
text: 'Use Redux',
completed: false,
id: 0
}
])
})
}) VisibilityFilter.js
import { VisibilityFilters } from '../actions'
const visibilityFilter = (state = VisibilityFilters.SHOW_ALL, action) => {
switch (action.type) {
case 'SET_VISIBILITY_FILTER':
return action.filter
default:
return state
}
}
export default visibilityFilter 步骤5： 组件
它是一个表示组件，它关心事物的外观，如标记、样式。它接收数据并仅通过props调用回调。它不知道数据来自何处，也不知道如何更改数据。它只呈现给他们的东西。
App.js
它是在UI中呈现所有内容的根组件。
import React from 'react'
import Footer from './Footer'
import AddTodo from '../containers/AddTodo'
import VisibleTodoList from '../containers/VisibleTodoList'
const App = () => (
<div>
<AddTodo />
<VisibleTodoList />
<Footer />
</div>
)
export default App
Footer.js
它告诉用户在哪里更改当前可见的todos。
import React from 'react'
import FilterLink from '../containers/FilterLink'
import { VisibilityFilters } from '../actions'
const Footer = () => (
<p>
Show: <FilterLink filter={VisibilityFilters.SHOW_ALL}>All</FilterLink>
{', '}
<FilterLink filter={VisibilityFilters.SHOW_ACTIVE}>Active</FilterLink>
{', '}
<FilterLink filter={VisibilityFilters.SHOW_COMPLETED}>Completed</FilterLink>
</p>
)
export default Footer Link.js
它是一个带有回调的链接。
import React from 'react'
import PropTypes from 'prop-types'
const Link = ({ active, children, onClick }) => {
if (active) {
return <span>{children}</span>
}
return (
<a
href=""
onClick={e => {
e.preventDefault()
onClick()
}}
>
{children}
</a>
)
}
Link.propTypes = {
active: PropTypes.bool.isRequired,
children: PropTypes.node.isRequired,
onClick: PropTypes.func.isRequired
}
export default Link Todo.js
它表示一个显示文本的todo项。
import React from 'react'
import PropTypes from 'prop-types'
const Todo = ({ onClick, completed, text }) => (
<li
onClick={onClick}
style={{
textDecoration: completed ? 'line-through' : 'none'
}}
>
{text}
</li>
)
Todo.propTypes = {
onClick: PropTypes.func.isRequired,
completed: PropTypes.bool.isRequired,
text: PropTypes.string.isRequired
}
export default Todo TodoList.js
它是一个列表显示可见的todos{id, text, completed}。
import React from 'react'
import PropTypes from 'prop-types'
import Todo from './Todo'
const TodoList = ({ todos, onTodoClick }) => (
<ul>
{todos.map((todo, index) => (
<Todo key={index} {...todo} onClick={() => onTodoClick(index)} />
))}
</ul>
)
TodoList.propTypes = {
todos: PropTypes.arrayOf(
PropTypes.shape({
id: PropTypes.number.isRequired,
completed: PropTypes.bool.isRequired,
text: PropTypes.string.isRequired
}).isRequired
).isRequired,
onTodoClick: PropTypes.func.isRequired
}
export default TodoList 步骤6：容器
它是一个容器组件，负责处理数据获取、更新状态等工作。它为表示组件或其他容器组件提供数据和行为，它使用Redux状态来读取数据并分派Redux动作来更新数据。
AddTodo.js
它包含带有ADD (submit)按钮的输入字段。
import React from 'react'
import { connect } from 'react-redux'
import { addTodo } from '../actions'
const AddTodo = ({ dispatch }) => {
let input
return (
<div>
<form onSubmit={e => {
e.preventDefault()
if (!input.value.trim()) {
return
}
dispatch(addTodo(input.value))
input.value = ''
}}>
<input ref={node => input = node} />
<button type="submit">
Add Todo
</button>
</form>
</div>
)
}
export default connect()(AddTodo) FilterLink.js
它表示当前的可见的filter并呈现一个链接。
import { connect } from 'react-redux'
import { setVisibilityFilter } from '../actions'
import Link from '../components/Link'
const mapStateToProps = (state, ownProps) => ({
active: ownProps.filter === state.visibilityFilter
})
const mapDispatchToProps = (dispatch, ownProps) => ({
onClick: () => dispatch(setVisibilityFilter(ownProps.filter))
})
export default connect(
mapStateToProps,
mapDispatchToProps
)(Link) VisibleTodoList.js
它过滤todos并呈现TodoList。
import { connect } from 'react-redux'
import { toggleTodo } from '../actions'
import TodoList from '../components/TodoList'
import { VisibilityFilters } from '../actions'
const getVisibleTodos = (todos, filter) => {
switch (filter) {
case VisibilityFilters.SHOW_ALL:
return todos
case VisibilityFilters.SHOW_COMPLETED:
return todos.filter(t => t.completed)
case VisibilityFilters.SHOW_ACTIVE:
return todos.filter(t => !t.completed)
default:
throw new Error('Unknown filter: ' + filter)
}
}
const mapStateToProps = state => ({
todos: getVisibleTodos(state.todos, state.visibilityFilter)
})
const mapDispatchToProps = dispatch => ({
toggleTodo: id => dispatch(toggleTodo(id))
})
export default connect(
mapStateToProps,
mapDispatchToProps
)(TodoList) 步骤7：储存
所有容器组件都需要访问Redux存储才能订阅它。为此，我们需要将它(存储)作为一个props传递给每个容器组件，但是我们建议使用特殊的React Redux组件，它使存储对所有容器组件可用，而无需显式地传递它。它只在呈现根组件时使用一次。
index.js
import React from 'react'
import { render } from 'react-dom'
import { createStore } from 'redux'
import { Provider } from 'react-redux'
import App from './components/App'
import rootReducer from './reducers'
const store = createStore(rootReducer)
render(
<Provider store={store}>
<App />
</Provider>,
document.getElementById('root')
)
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