Code to be refactored:
let nextTodoId = 0;
class TodoApp extends Component {
render() {
const {
todos,
visibilityFilter
} = this.props;
const visibleTodos = getVisibleTodos(
todos,
visibilityFilter
);
return (
<div>
<input ref={node => {
this.input = node;
}} />
<button onClick={() => {
store.dispatch({
type: 'ADD_TODO',
text: this.input.value,
id: nextTodoId++
});
this.input.value = '';
}}>
Add Todo
</button>
<ul>
{visibleTodos.map(todo =>
<li key={todo.id}
onClick={() => {
store.dispatch({
type: 'TOGGLE_TODO',
id: todo.id
});
}}
style={{
textDecoration:
todo.completed ?
'line-through' :
'none'
}}>
{todo.text}
</li>
)}
</ul>
<p>
Show:
{' '}
<FilterLink
filter='SHOW_ALL'
currentFilter={visibilityFilter}
>
All
</FilterLink>
{', '}
<FilterLink
filter='SHOW_ACTIVE'
currentFilter={visibilityFilter}
>
Active
</FilterLink>
{', '}
<FilterLink
filter='SHOW_COMPLETED'
currentFilter={visibilityFilter}
>
Completed
</FilterLink>
</p>
</div>
);
}
}
const FilterLink = ({
filter,
currentFilter,
children
}) => {
if (filter === currentFilter) {
return <span>{children}</span>;
}
return (
<a href='#'
onClick={e => {
e.preventDefault();
store.dispatch({
type: 'SET_VISIBILITY_FILTER',
filter
});
}}
>
{children}
</a>
);
};
Refactor footer part into a functional component, which contains all these three filter links. Pass in visibilityFilter as props:
const Footer = ({
visibilityFilter
}) => (
<p>
Show:
{' '}
<FilterLink
filter='SHOW_ALL'
currentFilter={visibilityFilter}
>
All
</FilterLink>
{', '}
<FilterLink
filter='SHOW_ACTIVE'
currentFilter={visibilityFilter}
>
Active
</FilterLink>
{', '}
<FilterLink
filter='SHOW_COMPLETED'
currentFilter={visibilityFilter}
>
Completed
</FilterLink>
</p>
);
In the FilterLink, we want it to be presentational components. However, the filter link includes a short dispatch call. I am replacing it with an on click call. I pass the filter as the single parameter for the calling component's convenience. I add on click to the props.
const FilterLink = ({
filter,
currentFilter,
children,
onFilterClick
}) => {
if (filter === currentFilter) {
return <span>{children}</span>;
}
return (
<a href='#'
onClick={e => {
e.preventDefault();
onFilterClick(filter);
}}
>
{children}
</a>
);
};
const Footer = ({
visibilityFilter,
onFilterClick
}) => (
<p>
Show:
{' '}
<FilterLink
filter='SHOW_ALL'
currentFilter={visibilityFilter}
onFilterClick={onFilterClick}
>
All
</FilterLink>
{', '}
<FilterLink
filter='SHOW_ACTIVE'
currentFilter={visibilityFilter}
onFilterClick={onFilterClick}
>
Active
</FilterLink>
{', '}
<FilterLink
filter='SHOW_COMPLETED'
currentFilter={visibilityFilter}
onFilterClick={onFilterClick}
>
Completed
</FilterLink>
</p>
);
-----------------------------------
Code:
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;
}
};
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
) => {
switch (action.type) {
case 'SET_VISIBILITY_FILTER':
return action.filter;
default:
return state;
}
};
const { combineReducers } = Redux;
const todoApp = combineReducers({
todos,
visibilityFilter
});
const { createStore } = Redux;
const store = createStore(todoApp);
const { Component } = React;
/**
Functional compoment, persental compoment: doesn't need to know what to do, just show the interface, call the callback function.
*/
const AddTodo = ({
onAddTodo
}) => {
let input;
return (
<div>
<input ref={node => {
input = node;
}} />
<button onClick={() => {
onAddTodo(input.value);
input.value = '';
}}>
Add Todo
</button>
</div>
);
}
/* Functional component */
const Footer = ({
visibilityFilter,
onFilterClick
}) => (
<p>
Show:
{' '}
<FilterLink
filter='SHOW_ALL'
currentFilter={visibilityFilter}
onFilterClick={onFilterClick}
>
All
</FilterLink>
{', '}
<FilterLink
filter='SHOW_ACTIVE'
currentFilter={visibilityFilter}
onFilterClick={onFilterClick}
>
Active
</FilterLink>
{', '}
<FilterLink
filter='SHOW_COMPLETED'
currentFilter={visibilityFilter}
onFilterClick={onFilterClick}
>
Completed
</FilterLink>
</p>
);
const FilterLink = ({
filter,
currentFilter,
children,
onFilterClick
}) => {
if (filter === currentFilter) {
return <span>{children}</span>;
}
return (
<a href='#'
onClick={e => {
e.preventDefault();
onFilterClick(filter);
}}
>
{children}
</a>
);
};
const getVisibleTodos = (
todos,
filter
) => {
switch (filter) {
case 'SHOW_ALL':
return todos;
case 'SHOW_COMPLETED':
return todos.filter(
t => t.completed
);
case 'SHOW_ACTIVE':
return todos.filter(
t => !t.completed
);
}
}
let nextTodoId = 0;
class TodoApp extends Component {
render() {
const {
todos,
visibilityFilter
} = this.props;
const visibleTodos = getVisibleTodos(
todos,
visibilityFilter
);
return (
<div>
<AddTodo
onAddTodo={ text =>
store.dispatch({
type: 'ADD_TODO',
id: nextTodoId++,
text
})
}
/>
<ul>
{visibleTodos.map(todo =>
<li key={todo.id}
onClick={() => {
store.dispatch({
type: 'TOGGLE_TODO',
id: todo.id
});
}}
style={{
textDecoration:
todo.completed ?
'line-through' :
'none'
}}>
{todo.text}
</li>
)}
</ul>
<Footer
visibilityFilter = {visibilityFilter}
onFilterClick={ (filter) => {
store.dispatch({
type: 'SET_VISIBILITY_FILTER',
filter
});
}}
/>
</div>
);
}
}
const render = () => {
ReactDOM.render(
<TodoApp
{...store.getState()}
/>,
document.getElementById('root')
);
};
store.subscribe(render);
render();