raydot/index.html

## index.html
<!DOCTYPE html>
<html>
<head>
<meta name="description" content="Video 21 -- Extracting Presentational Components">
  <meta charset="utf-8">
  <title>Redux Tutorial</title>
  <script src="https://cdnjs.cloudflare.com/ajax/libs/redux/4.0.4/redux.min.js"></script>
  <script crossorigin src="https://unpkg.com/react@16/umd/react.development.js"></script>
<script crossorigin src="https://unpkg.com/react-dom@16/umd/react-dom.development.js"></script>
</head>
<body>
  <div id='root'></div>
<script id="jsbin-javascript">
// Extracting and refactoring.

// Renders a single list item
'use strict';

var _extends = Object.assign || function (target) { for (var i = 1; i < arguments.length; i++) { var source = arguments[i]; for (var key in source) { if (Object.prototype.hasOwnProperty.call(source, key)) { target[key] = source[key]; } } } return target; };

function _toConsumableArray(arr) { if (Array.isArray(arr)) { for (var i = 0, arr2 = Array(arr.length); i < arr.length; i++) arr2[i] = arr[i]; return arr2; } else { return Array.from(arr); } }

var todo = function 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 _extends({}, state, {
                completed: !state.completed
            });
        default:
            return state;
    }
};

// todos reducer
var todos = function todos(state, action) {
    if (state === undefined) state = [];

    switch (action.type) {
        case 'ADD_TODO':
            return [].concat(_toConsumableArray(state), [// return array with all items + new
            todo(undefined, action) // calls child reducers
            ]);
        case 'TOGGLE_TODO':
            return state.map(function (t) {
                return todo(t, action);
            });
        default:
            return state;
    }
};

var visibilityFilter = function visibilityFilter(state, action) {
    if (state === undefined) state = 'SHOW_ALL';

    switch (action.type) {
        case 'SET_VISIBILITY_FILTER':
            return action.filter;
        default:
            return state;
    }
};

var _Redux = Redux;
var combineReducers = _Redux.combineReducers;

// This is the root reducer
var todoApp = combineReducers({
    todos: todos,
    visibilityFilter: visibilityFilter
});

var _Redux2 = Redux;
var createStore = _Redux2.createStore;

// combined reducer
var store = createStore(todoApp);

var _React = React;
var Component = _React.Component;

// react component for utilizing visibility filter
var FilterLink = function FilterLink(_ref) {
    var filter = _ref.filter;
    var currentFilter = _ref.currentFilter;
    var children = _ref.children;
    var onClick = _ref.onClick;

    if (filter === currentFilter) {
        return React.createElement(
            'span',
            null,
            children
        );
    }

    return React.createElement(
        'a',
        { href: '#',
            onClick: function (e) {
                e.preventDefault();
                onClick(filter);
            }
        },
        children
    );
};

var Footer = function Footer(_ref2) {
    var visibilityFilter = _ref2.visibilityFilter;
    var onFilterClick = _ref2.onFilterClick;
    return React.createElement(
        'p',
        null,
        'Show:',
        ' ',
        React.createElement(
            FilterLink,
            {
                filter: 'SHOW_ALL',
                currentFilter: visibilityFilter,
                onClick: onFilterClick
            },
            'All'
        ),
        ', ',
        React.createElement(
            FilterLink,
            {
                filter: 'SHOW_ACTIVE',
                currentFilter: visibilityFilter,
                onClick: onFilterClick
            },
            'Active'
        ),
        ', ',
        React.createElement(
            FilterLink,
            {
                filter: 'SHOW_COMPLETED',
                currentFilter: visibilityFilter,
                onClick: onFilterClick
            },
            'Completed'
        )
    );
};

// Purely presentational Todo component
var Todo = function Todo(_ref3) {
    var onClick = _ref3.onClick;
    var completed = _ref3.completed;
    var text = _ref3.text;
    var id = _ref3.id;
    return React.createElement(
        'li',
        {
            onClick: onClick,
            style: {
                textDecoration: completed ? 'line-through' : 'none'
            }
        },
        id,
        ': ',
        text
    );
};

// Purely presentational TodoList
var TodoList = function TodoList(_ref4) {
    var todos = _ref4.todos;
    var onTodoClick = _ref4.onTodoClick;
    return React.createElement(
        'ul',
        null,
        todos.map(function (todo) {
            return React.createElement(Todo, _extends({
                key: todo.id
            }, todo, {
                onClick: function () {
                    return onTodoClick(todo.id);
                }
            }));
        })
    );
};

// Purely presentational AddTodo
var AddTodo = function AddTodo(_ref5) {
    var onAddClick = _ref5.onAddClick;

    var input = undefined;

    return React.createElement(
        'div',
        null,
        React.createElement('input', { ref: function (node) {
                input = node;
            } }),
        React.createElement(
            'button',
            { onClick: function () {
                    onAddClick(input.value);
                    input.value = '';
                } },
            'Add Todo'
        )
    );
};

var getVisibleTodos = function getVisibleTodos(todos, filter) {
    switch (filter) {
        case 'SHOW_ALL':
            return todos;
        case 'SHOW_COMPLETED':
            return todos.filter(function (t) {
                return t.completed;
            });
        case 'SHOW_ACTIVE':
            return todos.filter(function (t) {
                return !t.completed;
            });
    }
};

var nextTodoId = 0;

// With the refactor of TodoList, AddTodo, and Footer, TodoApp() this is now acting as a container component.
var TodoApp = function TodoApp(_ref6) {
    var todos = _ref6.todos;
    var visibilityFilter = _ref6.visibilityFilter;
    return React.createElement(
        'div',
        null,
        React.createElement(AddTodo, {
            onAddClick: function (text) {
                return store.dispatch({
                    type: 'ADD_TODO',
                    id: nextTodoId++,
                    text: text
                });
            }
        }),
        React.createElement(TodoList, {
            todos: getVisibleTodos(todos, visibilityFilter),
            onTodoClick: function (id) {
                return store.dispatch({
                    type: 'TOGGLE_TODO',
                    id: id
                });
            }
        }),
        React.createElement(Footer, {
            visibilityFilter: visibilityFilter,
            onFilterClick: function (filter) {
                return store.dispatch({
                    type: 'SET_VISIBILITY_FILTER',
                    filter: filter
                });
            }
        })
    );
};

var render = function render() {
    ReactDOM.render(
    // passes to component as prop, every state filled in inside the state object.
    React.createElement(TodoApp, store.getState()), document.getElementById('root'));
};

store.subscribe(render); // runs on any state change
render();
</script>


<script id="jsbin-source-javascript" type="text/javascript">// Extracting and refactoring.

// Renders a single list item
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
    }
  }

  // todos reducer
  const todos = (state = [], action) => {
    switch (action.type) {
      case 'ADD_TODO':
        return [
          ...state, // return array with all items + new
          todo(undefined, action) // calls child reducers
        ]
        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

  // This is the root reducer
  const todoApp = combineReducers({
    todos,
    visibilityFilter
  })

  const { createStore } = Redux

  // combined reducer
  const store = createStore(todoApp)

  const { Component } = React

  // react component for utilizing visibility filter
const FilterLink = ({
    filter,
    currentFilter,
    children,
    onClick
}) => {
    if (filter === currentFilter) {
        return (
            <span>{children}</span>
        );
    }

    return (
        <a href='#'
            onClick={e => {
                e.preventDefault();
                onClick(filter)
            }}
        >
            {children}
        </a>
    )
}

const Footer = ({
    visibilityFilter,
    onFilterClick
}) => (
    <p>
        Show:
        {' '}
        <FilterLink
            filter='SHOW_ALL'
            currentFilter={visibilityFilter}
            onClick={onFilterClick}
        >
            All
        </FilterLink>
        {', '}
        <FilterLink
            filter='SHOW_ACTIVE'
            currentFilter={visibilityFilter}
            onClick={onFilterClick}
        >
            Active
        </FilterLink>
        {', '}
        <FilterLink
            filter='SHOW_COMPLETED'
            currentFilter={visibilityFilter}
            onClick={onFilterClick}
        >
            Completed
        </FilterLink>
    </p>
);

// Purely presentational Todo component
const Todo = ({
    onClick,
    completed,
    text,
    id
}) => (
    <li
        onClick={onClick}
        style={{
            textDecoration:
                completed ?
                'line-through' :
                'none'
        }}
    >
    {id}: {text}
    </li>
);

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

// Purely presentational AddTodo
const AddTodo = ({
  onAddClick
}) => {
  let input;

  return (
    <div>
        <input ref={node => {
          input = node;
          }} />
          <button onClick = {() => {
            onAddClick(input.value);
            input.value='';
          }}>
        Add Todo
       </button>
     </div>
  );
};

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;

 // With the refactor of TodoList, AddTodo, and Footer, TodoApp() this is now acting as a container component.
const TodoApp =({
    todos,
    visibilityFilter
}) => (
    <div>
        <AddTodo
            onAddClick={text =>
                store.dispatch({
                    type: 'ADD_TODO',
                    id: nextTodoId++,
                    text
                })
            }
        />
        <TodoList
            todos = {
                getVisibleTodos(
                    todos,
                    visibilityFilter
                )
            }
            onTodoClick = {id =>
                store.dispatch({
                    type: 'TOGGLE_TODO',
                    id
                })
            }
        />
        <Footer
            visibilityFilter={visibilityFilter}
            onFilterClick={filter =>
                store.dispatch({
                    type: 'SET_VISIBILITY_FILTER',
                    filter
                })
            }
        />
    </div>
);

const render = () => {
    ReactDOM.render(
        // passes to component as prop, every state filled in inside the state object.
        <TodoApp
            {...store.getState()}
        />,
        document.getElementById('root')
    )
}

store.subscribe(render) // runs on any state change
render()</script></body>
</html>

## jsbin.neseqom.js
// Extracting and refactoring.

// Renders a single list item
'use strict';

var _extends = Object.assign || function (target) { for (var i = 1; i < arguments.length; i++) { var source = arguments[i]; for (var key in source) { if (Object.prototype.hasOwnProperty.call(source, key)) { target[key] = source[key]; } } } return target; };

function _toConsumableArray(arr) { if (Array.isArray(arr)) { for (var i = 0, arr2 = Array(arr.length); i < arr.length; i++) arr2[i] = arr[i]; return arr2; } else { return Array.from(arr); } }

var todo = function 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 _extends({}, state, {
                completed: !state.completed
            });
        default:
            return state;
    }
};

// todos reducer
var todos = function todos(state, action) {
    if (state === undefined) state = [];

    switch (action.type) {
        case 'ADD_TODO':
            return [].concat(_toConsumableArray(state), [// return array with all items + new
            todo(undefined, action) // calls child reducers
            ]);
        case 'TOGGLE_TODO':
            return state.map(function (t) {
                return todo(t, action);
            });
        default:
            return state;
    }
};

var visibilityFilter = function visibilityFilter(state, action) {
    if (state === undefined) state = 'SHOW_ALL';

    switch (action.type) {
        case 'SET_VISIBILITY_FILTER':
            return action.filter;
        default:
            return state;
    }
};

var _Redux = Redux;
var combineReducers = _Redux.combineReducers;

// This is the root reducer
var todoApp = combineReducers({
    todos: todos,
    visibilityFilter: visibilityFilter
});

var _Redux2 = Redux;
var createStore = _Redux2.createStore;

// combined reducer
var store = createStore(todoApp);

var _React = React;
var Component = _React.Component;

// react component for utilizing visibility filter
var FilterLink = function FilterLink(_ref) {
    var filter = _ref.filter;
    var currentFilter = _ref.currentFilter;
    var children = _ref.children;
    var onClick = _ref.onClick;

    if (filter === currentFilter) {
        return React.createElement(
            'span',
            null,
            children
        );
    }

    return React.createElement(
        'a',
        { href: '#',
            onClick: function (e) {
                e.preventDefault();
                onClick(filter);
            }
        },
        children
    );
};

var Footer = function Footer(_ref2) {
    var visibilityFilter = _ref2.visibilityFilter;
    var onFilterClick = _ref2.onFilterClick;
    return React.createElement(
        'p',
        null,
        'Show:',
        ' ',
        React.createElement(
            FilterLink,
            {
                filter: 'SHOW_ALL',
                currentFilter: visibilityFilter,
                onClick: onFilterClick
            },
            'All'
        ),
        ', ',
        React.createElement(
            FilterLink,
            {
                filter: 'SHOW_ACTIVE',
                currentFilter: visibilityFilter,
                onClick: onFilterClick
            },
            'Active'
        ),
        ', ',
        React.createElement(
            FilterLink,
            {
                filter: 'SHOW_COMPLETED',
                currentFilter: visibilityFilter,
                onClick: onFilterClick
            },
            'Completed'
        )
    );
};

// Purely presentational Todo component
var Todo = function Todo(_ref3) {
    var onClick = _ref3.onClick;
    var completed = _ref3.completed;
    var text = _ref3.text;
    var id = _ref3.id;
    return React.createElement(
        'li',
        {
            onClick: onClick,
            style: {
                textDecoration: completed ? 'line-through' : 'none'
            }
        },
        id,
        ': ',
        text
    );
};

// Purely presentational TodoList
var TodoList = function TodoList(_ref4) {
    var todos = _ref4.todos;
    var onTodoClick = _ref4.onTodoClick;
    return React.createElement(
        'ul',
        null,
        todos.map(function (todo) {
            return React.createElement(Todo, _extends({
                key: todo.id
            }, todo, {
                onClick: function () {
                    return onTodoClick(todo.id);
                }
            }));
        })
    );
};

// Purely presentational AddTodo
var AddTodo = function AddTodo(_ref5) {
    var onAddClick = _ref5.onAddClick;

    var input = undefined;

    return React.createElement(
        'div',
        null,
        React.createElement('input', { ref: function (node) {
                input = node;
            } }),
        React.createElement(
            'button',
            { onClick: function () {
                    onAddClick(input.value);
                    input.value = '';
                } },
            'Add Todo'
        )
    );
};

var getVisibleTodos = function getVisibleTodos(todos, filter) {
    switch (filter) {
        case 'SHOW_ALL':
            return todos;
        case 'SHOW_COMPLETED':
            return todos.filter(function (t) {
                return t.completed;
            });
        case 'SHOW_ACTIVE':
            return todos.filter(function (t) {
                return !t.completed;
            });
    }
};

var nextTodoId = 0;

// With the refactor of TodoList, AddTodo, and Footer, TodoApp() this is now acting as a container component.
var TodoApp = function TodoApp(_ref6) {
    var todos = _ref6.todos;
    var visibilityFilter = _ref6.visibilityFilter;
    return React.createElement(
        'div',
        null,
        React.createElement(AddTodo, {
            onAddClick: function (text) {
                return store.dispatch({
                    type: 'ADD_TODO',
                    id: nextTodoId++,
                    text: text
                });
            }
        }),
        React.createElement(TodoList, {
            todos: getVisibleTodos(todos, visibilityFilter),
            onTodoClick: function (id) {
                return store.dispatch({
                    type: 'TOGGLE_TODO',
                    id: id
                });
            }
        }),
        React.createElement(Footer, {
            visibilityFilter: visibilityFilter,
            onFilterClick: function (filter) {
                return store.dispatch({
                    type: 'SET_VISIBILITY_FILTER',
                    filter: filter
                });
            }
        })
    );
};

var render = function render() {
    ReactDOM.render(
    // passes to component as prop, every state filled in inside the state object.
    React.createElement(TodoApp, store.getState()), document.getElementById('root'));
};

store.subscribe(render); // runs on any state change
render();
	<!DOCTYPE html>
	<html>
	<head>
	<meta name="description" content="Video 21 -- Extracting Presentational Components">
	<meta charset="utf-8">
	<title>Redux Tutorial</title>
	<script src="https://cdnjs.cloudflare.com/ajax/libs/redux/4.0.4/redux.min.js"></script>
	<script crossorigin src="https://unpkg.com/react@16/umd/react.development.js"></script>
	<script crossorigin src="https://unpkg.com/react-dom@16/umd/react-dom.development.js"></script>
	</head>
	<body>
	<div id='root'></div>
	<script id="jsbin-javascript">
	// Extracting and refactoring.

	// Renders a single list item
	'use strict';

	var _extends = Object.assign \|\| function (target) { for (var i = 1; i < arguments.length; i++) { var source = arguments[i]; for (var key in source) { if (Object.prototype.hasOwnProperty.call(source, key)) { target[key] = source[key]; } } } return target; };

	function _toConsumableArray(arr) { if (Array.isArray(arr)) { for (var i = 0, arr2 = Array(arr.length); i < arr.length; i++) arr2[i] = arr[i]; return arr2; } else { return Array.from(arr); } }

	var todo = function 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 _extends({}, state, {
	completed: !state.completed
	});
	default:
	return state;
	}
	};

	// todos reducer
	var todos = function todos(state, action) {
	if (state === undefined) state = [];

	switch (action.type) {
	case 'ADD_TODO':
	return [].concat(_toConsumableArray(state), [// return array with all items + new
	todo(undefined, action) // calls child reducers
	]);
	case 'TOGGLE_TODO':
	return state.map(function (t) {
	return todo(t, action);
	});
	default:
	return state;
	}
	};

	var visibilityFilter = function visibilityFilter(state, action) {
	if (state === undefined) state = 'SHOW_ALL';

	switch (action.type) {
	case 'SET_VISIBILITY_FILTER':
	return action.filter;
	default:
	return state;
	}
	};

	var _Redux = Redux;
	var combineReducers = _Redux.combineReducers;

	// This is the root reducer
	var todoApp = combineReducers({
	todos: todos,
	visibilityFilter: visibilityFilter
	});

	var _Redux2 = Redux;
	var createStore = _Redux2.createStore;

	// combined reducer
	var store = createStore(todoApp);

	var _React = React;
	var Component = _React.Component;

	// react component for utilizing visibility filter
	var FilterLink = function FilterLink(_ref) {
	var filter = _ref.filter;
	var currentFilter = _ref.currentFilter;
	var children = _ref.children;
	var onClick = _ref.onClick;

	if (filter === currentFilter) {
	return React.createElement(
	'span',
	null,
	children
	);
	}

	return React.createElement(
	'a',
	{ href: '#',
	onClick: function (e) {
	e.preventDefault();
	onClick(filter);
	}
	},
	children
	);
	};

	var Footer = function Footer(_ref2) {
	var visibilityFilter = _ref2.visibilityFilter;
	var onFilterClick = _ref2.onFilterClick;
	return React.createElement(
	'p',
	null,
	'Show:',
	' ',
	React.createElement(
	FilterLink,
	{
	filter: 'SHOW_ALL',
	currentFilter: visibilityFilter,
	onClick: onFilterClick
	},
	'All'
	),
	', ',
	React.createElement(
	FilterLink,
	{
	filter: 'SHOW_ACTIVE',
	currentFilter: visibilityFilter,
	onClick: onFilterClick
	},
	'Active'
	),
	', ',
	React.createElement(
	FilterLink,
	{
	filter: 'SHOW_COMPLETED',
	currentFilter: visibilityFilter,
	onClick: onFilterClick
	},
	'Completed'
	)
	);
	};

	// Purely presentational Todo component
	var Todo = function Todo(_ref3) {
	var onClick = _ref3.onClick;
	var completed = _ref3.completed;
	var text = _ref3.text;
	var id = _ref3.id;
	return React.createElement(
	'li',
	{
	onClick: onClick,
	style: {
	textDecoration: completed ? 'line-through' : 'none'
	}
	},
	id,
	': ',
	text
	);
	};

	// Purely presentational TodoList
	var TodoList = function TodoList(_ref4) {
	var todos = _ref4.todos;
	var onTodoClick = _ref4.onTodoClick;
	return React.createElement(
	'ul',
	null,
	todos.map(function (todo) {
	return React.createElement(Todo, _extends({
	key: todo.id
	}, todo, {
	onClick: function () {
	return onTodoClick(todo.id);
	}
	}));
	})
	);
	};

	// Purely presentational AddTodo
	var AddTodo = function AddTodo(_ref5) {
	var onAddClick = _ref5.onAddClick;

	var input = undefined;

	return React.createElement(
	'div',
	null,
	React.createElement('input', { ref: function (node) {
	input = node;
	} }),
	React.createElement(
	'button',
	{ onClick: function () {
	onAddClick(input.value);
	input.value = '';
	} },
	'Add Todo'
	)
	);
	};

	var getVisibleTodos = function getVisibleTodos(todos, filter) {
	switch (filter) {
	case 'SHOW_ALL':
	return todos;
	case 'SHOW_COMPLETED':
	return todos.filter(function (t) {
	return t.completed;
	});
	case 'SHOW_ACTIVE':
	return todos.filter(function (t) {
	return !t.completed;
	});
	}
	};

	var nextTodoId = 0;

	// With the refactor of TodoList, AddTodo, and Footer, TodoApp() this is now acting as a container component.
	var TodoApp = function TodoApp(_ref6) {
	var todos = _ref6.todos;
	var visibilityFilter = _ref6.visibilityFilter;
	return React.createElement(
	'div',
	null,
	React.createElement(AddTodo, {
	onAddClick: function (text) {
	return store.dispatch({
	type: 'ADD_TODO',
	id: nextTodoId++,
	text: text
	});
	}
	}),
	React.createElement(TodoList, {
	todos: getVisibleTodos(todos, visibilityFilter),
	onTodoClick: function (id) {
	return store.dispatch({
	type: 'TOGGLE_TODO',
	id: id
	});
	}
	}),
	React.createElement(Footer, {
	visibilityFilter: visibilityFilter,
	onFilterClick: function (filter) {
	return store.dispatch({
	type: 'SET_VISIBILITY_FILTER',
	filter: filter
	});
	}
	})
	);
	};

	var render = function render() {
	ReactDOM.render(
	// passes to component as prop, every state filled in inside the state object.
	React.createElement(TodoApp, store.getState()), document.getElementById('root'));
	};

	store.subscribe(render); // runs on any state change
	render();
	</script>



	<script id="jsbin-source-javascript" type="text/javascript">// Extracting and refactoring.

	// Renders a single list item
	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
	}
	}

	// todos reducer
	const todos = (state = [], action) => {
	switch (action.type) {
	case 'ADD_TODO':
	return [
	...state, // return array with all items + new
	todo(undefined, action) // calls child reducers
	]
	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

	// This is the root reducer
	const todoApp = combineReducers({
	todos,
	visibilityFilter
	})

	const { createStore } = Redux

	// combined reducer
	const store = createStore(todoApp)

	const { Component } = React

	// react component for utilizing visibility filter
	const FilterLink = ({
	filter,
	currentFilter,
	children,
	onClick
	}) => {
	if (filter === currentFilter) {
	return (
	<span>{children}</span>
	);
	}

	return (
	<a href='#'
	onClick={e => {
	e.preventDefault();
	onClick(filter)
	}}
	>
	{children}
	</a>
	)
	}

	const Footer = ({
	visibilityFilter,
	onFilterClick
	}) => (
	<p>
	Show:
	{' '}
	<FilterLink
	filter='SHOW_ALL'
	currentFilter={visibilityFilter}
	onClick={onFilterClick}
	>
	All
	</FilterLink>
	{', '}
	<FilterLink
	filter='SHOW_ACTIVE'
	currentFilter={visibilityFilter}
	onClick={onFilterClick}
	>
	Active
	</FilterLink>
	{', '}
	<FilterLink
	filter='SHOW_COMPLETED'
	currentFilter={visibilityFilter}
	onClick={onFilterClick}
	>
	Completed
	</FilterLink>
	</p>
	);

	// Purely presentational Todo component
	const Todo = ({
	onClick,
	completed,
	text,
	id
	}) => (
	<li
	onClick={onClick}
	style={{
	textDecoration:
	completed ?
	'line-through' :
	'none'
	}}
	>
	{id}: {text}
	</li>
	);

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

	// Purely presentational AddTodo
	const AddTodo = ({
	onAddClick
	}) => {
	let input;

	return (
	<div>
	<input ref={node => {
	input = node;
	}} />
	<button onClick = {() => {
	onAddClick(input.value);
	input.value='';
	}}>
	Add Todo
	</button>
	</div>
	);
	};

	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;

	// With the refactor of TodoList, AddTodo, and Footer, TodoApp() this is now acting as a container component.
	const TodoApp =({
	todos,
	visibilityFilter
	}) => (
	<div>
	<AddTodo
	onAddClick={text =>
	store.dispatch({
	type: 'ADD_TODO',
	id: nextTodoId++,
	text
	})
	}
	/>
	<TodoList
	todos = {
	getVisibleTodos(
	todos,
	visibilityFilter
	)
	}
	onTodoClick = {id =>
	store.dispatch({
	type: 'TOGGLE_TODO',
	id
	})
	}
	/>
	<Footer
	visibilityFilter={visibilityFilter}
	onFilterClick={filter =>
	store.dispatch({
	type: 'SET_VISIBILITY_FILTER',
	filter
	})
	}
	/>
	</div>
	);

	const render = () => {
	ReactDOM.render(
	// passes to component as prop, every state filled in inside the state object.
	<TodoApp
	{...store.getState()}
	/>,
	document.getElementById('root')
	)
	}

	store.subscribe(render) // runs on any state change
	render()</script></body>
	</html>