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Minimal todo app with Redux from scratch
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const { Component } = React | |
// Model | |
let nextTodoID = 0 | |
// Update | |
const setVisibilityFilter = filter => ({ | |
type: 'SET_VISIBILITY_FILTER', | |
filter, | |
}) | |
const toggleTodo = id => ({ | |
type: 'TOGGLE_TODO', | |
id, | |
}) | |
const addTodo = text => ({ | |
type: 'ADD_TODO', | |
id: nextTodoID++, | |
text, | |
}) | |
const todo = (state, action) => { | |
switch(action.type) { | |
case 'ADD_TODO': | |
return { | |
id: action.id, | |
text: action.text, | |
completed: false, | |
} | |
case 'TOGGLE_TODO': | |
return action.id === state.id ? | |
{ ...state, completed: !state.completed } : | |
state | |
default: | |
return state | |
} | |
} | |
const todos = (state = [], action) => { | |
switch(action.type) { | |
case 'ADD_TODO': | |
return [ ...state, todo(undefined, action) ] | |
case 'TOGGLE_TODO': | |
return state.map(t => todo(t, action)) | |
default: | |
return state | |
} | |
} | |
const visibilityFilter = (state = 'SHOW_ALL', action) => { | |
return action.type === 'SET_VISIBILITY_FILTER' ? | |
action.filter : | |
state | |
} | |
// View | |
const Todos = () => ( | |
<div> | |
<AddTodo /> | |
<VisibleTodoList /> | |
<Footer /> | |
</div> | |
) | |
const Todo = ({ text, completed, onClick }) => ( | |
<li | |
onClick={onClick} | |
style={{ textDecoration: completed ? | |
'line-through' : 'none' | |
}} | |
>{text}</li> | |
) | |
const TodosList = ({ todos, onTodoClick }) => ( | |
<ul> | |
{todos.map(todo => | |
<Todo | |
key={todo.id} | |
{...todo} | |
onClick={() => onTodoClick(todo.id)} | |
/> | |
)} | |
</ul> | |
) | |
const AddTodo = (props, { store }) => { | |
let input | |
return ( | |
<div> | |
<input ref={node => { input = node }} /> | |
<button | |
onClick={() => { | |
store.dispatch(addTodo(input.value)) | |
input.value = "" | |
}}> | |
Add | |
</button> | |
</div> | |
) | |
} | |
AddTodo.contextTypes = { | |
store: React.PropTypes.object, | |
} | |
const Link = ({ active, onClick, children }) => active ? <span>{children}</span> : ( | |
<a | |
href="#" | |
onClick={onClick} | |
>{children}</a> | |
) | |
class FilterLink extends Component { | |
static contextTypes = { | |
store: React.PropTypes.object, | |
} | |
componentDidMount() { | |
this.unsubscribe = this.context.store.subscribe(() => this.forceUpdate()) | |
} | |
componentWillUnMount() { | |
this.unsubscribe() | |
} | |
render() { | |
const { children, filter } = this.props | |
const { visibilityFilter } = this.context.store.getState() | |
return ( | |
<Link | |
active={visibilityFilter === filter} | |
onClick={e => { | |
e.preventDefault() | |
this.context.store.dispatch(setVisibilityFilter(filter)) | |
}} | |
>{children}</Link> | |
) | |
} | |
} | |
class VisibleTodoList extends Component { | |
static contextTypes = { | |
store: React.PropTypes.object, | |
} | |
componentDidMount() { | |
this.unsubscribe = this.context.store.subscribe(() => this.forceUpdate()) | |
} | |
componentWillUnMount() { | |
this.unsubscribe() | |
} | |
filterTodos(todos, filter) { | |
switch(filter) { | |
case 'SHOW_ALL': | |
return todos | |
case 'SHOW_ACTIVE': | |
return todos.filter(t => !t.completed) | |
case 'SHOW_COMPLETED': | |
return todos.filter(t => t.completed) | |
} | |
} | |
render() { | |
const { todos, visibilityFilter } = this.context.store.getState() | |
return ( | |
<TodosList | |
todos={this.filterTodos(todos, visibilityFilter)} | |
onTodoClick={id => { | |
this.context.store.dispatch(toggleTodo(id)) | |
}} /> | |
) | |
} | |
} | |
const Footer = () => ( | |
<p> | |
Filters: | |
{' '} | |
<FilterLink | |
filter='SHOW_ALL' | |
>Show All</FilterLink> | |
{' '} | |
<FilterLink | |
filter='SHOW_ACTIVE' | |
>Active</FilterLink> | |
{' '} | |
<FilterLink | |
filter='SHOW_COMPLETED' | |
>Completed</FilterLink> | |
</p> | |
) | |
// Set Up | |
class Provider extends Component { | |
static childContextTypes = { | |
store: React.PropTypes.object | |
} | |
getChildContext() { | |
return { | |
store: this.props.store | |
} | |
} | |
render() { | |
return this.props.children | |
} | |
} | |
const combineReducers = reducers => ( | |
(state, action) => ( | |
Object.keys(reducers).reduce( | |
(nextState, key) => { | |
nextState[key] = reducers[key]( | |
state[key], action | |
) | |
return nextState | |
}, {} | |
) | |
) | |
) | |
const createStore = reducer => { | |
let state | |
let listeners = [] | |
try { | |
state = JSON.parse(localStorage.getItem('todos')) | |
} catch(e){ | |
state = {} | |
} | |
const getState = () => state | |
const dispatch = action => { | |
state = reducer(state, action) | |
console.log(state) | |
localStorage.setItem('todos', JSON.stringify(state)) | |
listeners.forEach(f => f()) | |
} | |
const subscribe = listener => { | |
listeners = [ ...listeners, listener ] | |
return () => { | |
listeners = listeners.filter(l => l !== listener) | |
} | |
} | |
dispatch({}) | |
return { getState, dispatch, subscribe } | |
} | |
const todoApp = combineReducers({ todos, visibilityFilter }) | |
ReactDOM.render(<Provider store={createStore(todoApp)}><Todos /></Provider>, document.getElementById('root')) |
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