Modulo TO DO com LocalStorage

todo.js

var APPMAIL = (function() {
	var box = {};
	box.txtEmail = document.querySelector('#email');
	box.btnAdicionar = document.querySelector('.pure-button');
	box.lstEmails = document.querySelector('ul');
	box.validateData = function() {
		box.txtEmail.focus();
		var pattern = /^\w{2,}\@\w+\.[a-zA-Z]{2,4}(\.[a-zA-Z]{2})?$/;
		if(pattern.test(box.txtEmail.value)) {
			box.txtEmail.className = "";
			return true;
		} else {
			box.txtEmail.className = "error";
			return false;
		}
	};
	box.saveData = function(email) {
		if(localStorage && localStorage.getItem("emailList")) {
			var lista = JSON.parse(localStorage.getItem("emailList"));
		} else {
			var lista = [];	
		}
		lista.push({account: email});
		localStorage.setItem("emailList", JSON.stringify(lista));
	};
	box.updateScreen = function() {
		if(localStorage && localStorage.getItem("emailList")) {
			var lista = JSON.parse(localStorage.getItem("emailList"));
			box.lstEmails.innerHTML = "";
			for(var i = 0; i < lista.length; i++) {
				var li = document.createElement('li');
				li.innerHTML = lista[i].account;
				box.lstEmails.appendChild(li);
			}
		}
	};
	box.initialize = function() {
		box.btnAdicionar.addEventListener("click", function(event) {
			event.preventDefault();
			if(box.validateData()) {
				box.saveData(box.txtEmail.value);
				box.txtEmail.value = "";
				box.updateScreen();
			}
		});
		box.updateScreen();
	}();
})();