localStorage with expiry date

app.data.js

// Save data with expiry date
var app = {
    data: ''
};

// Enhanced localStorage with expiry
app.data = {
    save: function(storageKey, value, expiry) {
        if (!expiry) {
            expiry = "360"; // Default expiry of 6 hours
        }
        var dueTime = expiry * 60 * 1E3;
        var data = {
            value: JSON.stringify(value),
            timestamp: (new Date).getTime() + dueTime
        };
        window.localStorage.setItem(storageKey, JSON.stringify(data));
        return value;
    },
    load: function(id) {
        var item = JSON.parse(window.localStorage.getItem(id));
        if (!item) {
            return false;
        }
        return (new Date).getTime() < item.timestamp && JSON.parse(item.value);
    }
};