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HTML

              
                <h1>Todo</h1>

<form id="todo-form">
	<label for="todo-item">What do you need to do?</label>
	<input type="text" name="todo-item" id="todo-item">
	<button class="btn" id="add-todo">Add Todo</button>
</form>

<div id="app"></div>
              
            
!

CSS

              
                /**
 * Add box sizing to everything
 * @link http://www.paulirish.com/2012/box-sizing-border-box-ftw/
 */
*,
*:before,
*:after {
	box-sizing: border-box;
}

/**
 * Layout
 */
body {
	font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "Roboto", "Oxygen", "Ubuntu", "Cantarell", "Fira Sans", "Droid Sans", "Helvetica Neue", sans-serif;
	font-size: 112.5%;
	margin-left: auto;
	margin-right: auto;
	max-width: 40em;
	width: 88%;
}

/**
 * Forms
 */

label,
[type="text"] {
	display: block;
	width: 100%;
}

label {
	margin-bottom: 0.25em;
}

[type="text"] {
	font-size: inherit;
	margin-bottom: 1em;
	padding: 0.25em 1em;
}

[type="checkbox"] {
	margin-right: 0.5em;
}

/**
 * Buttons
 */

.btn {
	background-color: #0088cc;
	border: 1px solid #0088cc;
	border-radius: 1px;
	color: #ffffff;
	display: inline-block;
	font-size: 0.9375em;
	font-weight: normal;
	line-height: 1.2;
	margin-right: 0.3125em;
	margin-bottom: 0.3125em;
	padding: 0.5em 0.6875em;
}

.btn:hover,
.btn:focus,
.btn:active {
	background-color: #005580;
	border-color: #005580;
	color: #ffffff;
	text-decoration: none;
}

/**
 * Todos
 */

.todos {
	list-style: none;
	margin-left: 0;
	padding-left: 0;
}

.todos .completed {
	text-decoration: line-through;
}

.todo:before,
.todo:after {
	display: table;
	content: " ";
}

.todo:after {
	clear: both;
}

.todo label {
	width: auto;
}

.todo label,
.todo button {
	float: left;
}

.todo button {
	margin-left: 0.5em;
}
              
            
!

JS

              
                //
// Variables
//

var todoField = document.querySelector('#todo-item');
var todo;


//
// Methods
//

/**
 * Save todo items to local storage
 */
var saveTodos = function () {
	localStorage.setItem('todos', JSON.stringify(todo.data.todos));
};

/**
 * Get todo items from local storage
 * @return {Array} The todo items (or an empty array if none exist)
 */
var getTodos = function () {
	var todos = localStorage.getItem('todos');
	if (todos) return JSON.parse(todos);
	return [];
};

/**
 * Setup the initial todo list container
 */
var setup = function () {

	// Create the todo list
	todo = new Reef('#app', {
		data: {
			todos: getTodos()
		},
		template: function (props) {

			// Create each todo item
			var template = props.todos.map(function (todo, index) {

				// If it's being edited, show a form
				if (todo.edit) {
					return `
						<li class="todo">
							<form class="todo-edit-form">
								<input type="text" class="todo-update" value="${todo.item}" data-todo-edit="${index}">
								<button>Save</button>
							</form>
						</li>`;
				}

				// Otherwise, show the item with a checkbox
				return `
					<li class="todo">
						<label ${todo.completed ? 'class="completed"' : ''}>
							<input data-todo="${index}" type="checkbox" ${todo.completed ? ' checked="checked"' : ''}>
							<span class="todo-item">${todo.item}</span>
						</label>
						<button class="todo-edit">Edit</button>
						<button class="todo-delete">Delete</button>
					</li>`;

			}).join('');

			// If there are todo items, wrap it in an unordered list
			if (template.length > 0) {
				return `<ul class="todos">${template}</ul><p><button class="todo-clear">Clear All Todos</button></p>`;
			}

			return '';

		}
	});

	// Render the todo list
	todo.render();

};

/**
 * Add a todo to the list
 */
var addTodo = function (event) {

	// Only run if there's an item to add
	if (todoField.value.length < 1) return;

	// Prevent default form submission
	event.preventDefault();

	// Update the state
	todo.data.todos.push({
		item: todoField.value,
		completed: false
	});

	// Clear the input field and return to focus
	todoField.value = '';
	todoField.focus();

};

/**
 * Mark a todo as complete (or incomplete)
 * @param  {Node} item  The todo item
 */
var completeTodo = function (item) {

	// Get the todo item
	var todoItem = todo.data.todos[item.getAttribute('data-todo')];
	if (!todoItem) return;

	// If it's completed, uncomplete it
	// Otherwise, mark is as complete
	if (todoItem.completed) {
		todoItem.completed = false;
	} else {
		todoItem.completed = true;
	}

};

/**
 * Delete a todo list item
 * @param  {Node} btn The delete button that was clicked
 */
var deleteTodo = function (btn) {

	// Get the index for the todo list item
	var index = btn.closest('.todo').querySelector('input').getAttribute('data-todo');
	if (!index) return;

	// Remove the item from state
	todo.data.todos.splice(index, 1);

};

/**
 * Edit a todo list item
 * @param  {Node} btn The edit button that was clicked
 */
var editTodo = function (btn) {

	// Get the todo list DOM element
	var todoListItem = btn.closest('.todo');
	if (!todoListItem) return;

	// Get the index for the item
	var index = todoListItem.querySelector('input').getAttribute('data-todo');
	if (!index) return;

	// Get the item from state
	var todoItem = todo.data.todos[index];
	if (!todoItem) return;

	// Update state
	todoItem.edit = true;

};

var saveEditTodo = function (event) {

	// Prevent default form submit
	event.preventDefault();

	// Get the todo list DOM node
	var newTodo = event.target.querySelector('.todo-update');
	if (!newTodo) return;

	// Get the todo list item index
	var index = newTodo.getAttribute('data-todo-edit');
	if (!index) return;

	// Get the item from state
	var todoItem = todo.data.todos[index];
	if (!todoItem) return;

	// If the item is empty, delete the todo item
	// Otherwise, update it
	if (newTodo.value.length < 1) {
		todo.data.todos.splice(index, 1);
	} else {
		todoItem.item = newTodo.value;
		todoItem.edit = false;
	}

};

/**
 * Remove all todo items from state
 */
var clearTodos = function () {

	// Replace the existing state with an empty array
	todo.data.todos = [];

};

/**
 * Handle click events
 */
var clickHandler = function (event) {

	// Complete todos
	var todo = event.target.closest('[data-todo]');
	if (todo) {
		completeTodo(todo);
	};

	// Edit todo
	var editBtn = event.target.closest('.todo-edit');
	if (editBtn) {
		editTodo(editBtn);
	}

	// Delete todo
	var deleteBtn = event.target.closest('.todo-delete');
	if (deleteBtn) {
		deleteTodo(deleteBtn);
	}

	// Clear all todos
	if (event.target.closest('.todo-clear')) {
		clearTodos();
	}
};

/**
 * Handle form submit events
 */
var submitHandler = function (event) {

	// If it's the "new todo" form, add the item
	if (event.target.matches('#todo-form')) {
		addTodo(event);
	}

	// If it's the "edit todo" form, save the edit
	if (event.target.matches('.todo-edit-form')) {
		saveEditTodo(event);
	}
};

/**
 * Handle render events
 */
var renderHandler = function (event) {

	// If the rendered element is not the #app, bail
	if (!event.target.matches('#app')) return;

	// Save the current state to localStorage
	saveTodos();

};


//
// Inits & Event Listeners
//

// Setup the DOM
setup();

// Listen for events
document.addEventListener('submit', submitHandler, false);
document.addEventListener('click', clickHandler, false);
document.addEventListener('render', renderHandler, false);
              
            
!
999px

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