Practice Set - localStorage

by Sub Taper

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"
}

// Convert the object to a string for local storage
var jsonPerson = JSON.stringify(personInfo);
// Stores the string in local storage
window.localStorage.setItem("person", jsonPerson);

// Get the string back out of local storage
var cValue = window.localStorage.getItem("person", jsonPerson);

// 
var backToObj = JSON.parse(cValue);

// create an object which will dump out all the properties of the object
function dumpObject(backToObj) {
    for (var key in backToObj) {
        // test to make sure its an object w properties
        if (backToObj.hasOwnProperty(key)) {
             logMessage( backToObj[key]);
        }
    }
}

 dumpObject(backToObj);





// 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>";
    }