[Redux] React Todo List Example (Adding a Todo)

时间:2021-01-31 06:48:59

Learn how to create a React todo list application using the reducers we wrote before.

/**
* A reducer for a single todo
* @param state
* @param action
* @returns {*}
*/
const todo = ( state, action ) => {
switch ( action.type ) {
case 'ADD_TODO':
return {
id: action.id,
text: action.text,
completed: false
};
case 'TOGGLE_TODO':
if ( state.id !== action.id ) {
return state;
} return {
...state,
completed: !state.completed
};
default:
return state;
}
}; /**
* The reducer for the todos
* @param state
* @param action
* @returns {*}
*/
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; }
}; /**
* Reducer for the visibilityFilter
* @param state
* @param action
* @returns {*}
*/
const visibilityFilter = ( state = 'SHOW_ALL',
action ) => {
switch ( action.type ) {
case 'SET_VISIBILITY_FILTER':
return action.filter;
default:
return state;
}
}; /**
* combineReducers: used for merge reducers togethger
* createStore: create a redux store
*/
const { combineReducers, createStore } = Redux;
const todoApp = combineReducers( {
todos,
visibilityFilter
} ); const store = createStore( todoApp ); /**
* For generate todo's id
* @type {number}
*/
let nextTodoId = 0; /**
* React related
*/
const {Component} = React;
class TodoApp extends Component {
render() {
return (
<div>
<input ref={
(node)=>{
this.input = node
}
}/>
<button onClick={
()=>{
//After clicking the button, dispatch a add todo action
store.dispatch({
type: 'ADD_TODO',
id: nextTodoId++,
text: this.input.value
})
this.input.value = "";
}
}>ADD todo
</button>
<ul>
//loop thought the todo list
{this.props.todos.map( ( todo )=> {
return <li key={todo.id}>{todo.text}</li>
} )}
</ul>
</div>
);
}
} const render = () => {
ReactDOM.render(
<TodoApp todos={store.getState().todos}/>,
document.getElementById( 'root' )
);
}; //Every time, store updated, also fire the render() function
store.subscribe( render );
render();
<!DOCTYPE html>
<html>
<head>
<script src="https://cdnjs.cloudflare.com/ajax/libs/redux/3.0.4/redux.js"></script>
<script src="https://fb.me/react-0.14.0.js"></script>
<script src="https://fb.me/react-dom-0.14.0.js"></script> <title>JS Bin</title>
</head>
<body> <div id="root"></div>
</body>
</html>