Redux Todos Example

此项目模板是使用Create React App构建的，它提供了一种简单的方法来启动React项目而无需构建配置。
使用Create-React-App构建的项目包括对ES6语法的支持，以及几种非官方/尚未最终形式的Javascript语法
先看效果

这个例子可以帮助你深入理解在 Redux 中 state 的更新与组件是如何共同运作的。
展示了 reducer 如何委派 action 给其它 reducer，也展示了如何使用 React Redux 从展示组件中生成容器组件。

//index.js 跟组件
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')
)

先看action,action是对象

let nextTodoId = 0
// Action 本质上是 JavaScript 普通对象。我们约定，action 内必须使用一个字符串类型的 type 字段来表示将要执行的动作。
// 多数情况下，type 会被定义成字符串常量。当应用规模越来越大时，建议使用单独的模块或文件来存放 action。
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'
}

接下来看reducer
这个是combineReducers

import { combineReducers } from 'redux'
import todos from './todos'
import visibilityFilter from './visibilityFilter'

export default combineReducers({
  todos,
  visibilityFilter
})

这个是reducer操作纯函数

//纯函数操作state
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

visibilityFilter.js中是进行过滤函数

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

//app.js
//这个是根APP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

这个是footer.js

//这是一个footer组件
import React from 'react'
import FilterLink from '../containers/FilterLink'
import { VisibilityFilters } from '../actions'

const Footer = () => (
  <div>
    <span>Show: </span>
    <FilterLink filter={VisibilityFilters.SHOW_ALL}>
      All
    </FilterLink>
    <FilterLink filter={VisibilityFilters.SHOW_ACTIVE}>
      Active
    </FilterLink>
    <FilterLink filter={VisibilityFilters.SHOW_COMPLETED}>
      Completed
    </FilterLink>
  </div>
)
export default Footer

//link组件
import React from 'react'
import PropTypes from 'prop-types'

const Link = ({ active, children, onClick }) => (
    <button
       onClick={onClick}
       disabled={active}
       style={{
           marginLeft: '4px',
       }}
    >
      {children}
    </button>
)

Link.propTypes = {
  active: PropTypes.bool.isRequired,
  children: PropTypes.node.isRequired,
  onClick: PropTypes.func.isRequired
}

export default Link

//todo组件
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

这个是todoList组件

import React from 'react'
import PropTypes from 'prop-types'
import Todo from './Todo'

const TodoList = ({ todos, toggleTodo }) => (
  <ul>
    {todos.map(todo =>
      <Todo
        key={todo.id}
        {...todo}
        onClick={() => toggleTodo(todo.id)}
      />
    )}
  </ul>
)

TodoList.propTypes = {
  todos: PropTypes.arrayOf(PropTypes.shape({
    id: PropTypes.number.isRequired,
    completed: PropTypes.bool.isRequired,
    text: PropTypes.string.isRequired
  }).isRequired).isRequired,
  toggleTodo: PropTypes.func.isRequired
}

export default TodoList

接下来展示了如何使用 React Redux 从展示组件中生成容器组件。
在container中的是AddTodo.js

//addtodo.js
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
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
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)