Practice Set - localStorage

by subsari

HTML

<p>There is one part to this practice problem. This exercise is designed to get you comfortable with using <code>window.localStorage</code>, the <a href="https://developer.mozilla.org/en-US/docs/Web/API/Storage" target="_blank">Storage object</a>, and the utilities of the <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/JSON/stringify" target="_blank">JSON object</a>.</p>
<ol>
    <li>On lines 11-12, the <code>personInfo</code> object is being converted into a string using JSON.stringify(), and assigned to localStorage. Your task is to do the opposite: retrieve the string from localStorage (Storage.getItem() may help), and output it to the page using the logMessage() function that's provided. 
    </li>
    <p><b>Output:</b>
    </p>
    <div id="output"></div>

CSS

#output {
    border:1px solid black;
    padding: .5em;
}

JavaScript

// Initialize our personInfo Object
var personInfo = {
    fname: "Bill",
    lname: "Adama",
    addr: "Galactica CIC",
    email: "N/A",
    title: "Admiral",
}

// Write the object to localStorage
var jsonPerson = JSON.stringify(personInfo);
window.localStorage.setItem("person", jsonPerson);

// Insert your code below to read the object back from localStorage,
// convert it back to an object, 
// and iterate over its properties, printing the property names and their 
// values using the logMessage() function. This last part should be
// identical to code you wrote for the previous pratice set
function loadFromLocalStorage(key){
	return JSON.parse(window.localStorage.getItem(key));
}

// Utility function for logging convenience
// Logs msg to the element with given id
// If id is undefined, logs to #output
function logMessage(msg, id) {
	if (!id) {
		id = "output";
	}
	document.getElementById(id).innerHTML += msg + "<br>";
}

// Utility function for logging object properties
function logProperties(obj){
	for (var k in obj){
		logMessage(k);
	}
}

// Main Function
function mainApp(){
	var person = loadFromLocalStorage("person");
	logProperties(person);
}

// Execute Main 
mainApp();