State persistence - localStorage

<!DOCTYPE html>
<html>
<head>
    <meta charset="utf-8" />
    <title>Localstorage example</title>
</head>
<body onload="testLocalStorage()">
    <script>
        function testLocalStorage() {
            let rv1 = localStorage.getItem("receiptValue");
            console.log(rv1); // Will print null, there's no value for this key

            // Set value for the key
            localStorage.setItem("receiptValue", 100);

            let rv2 = localStorage.getItem("receiptValue");
            console.log(rv2); // Will print value

            // Clear the storage
            localStorage.clear();

            let rv3 = localStorage.getItem("receiptValue");
            console.log(rv3); // Will print null, storage is empty

            // To set the complex value, use JSON serialization
            let complexValue = {
                a: 1,
                b: "Some text",
                c: [100, 200, 300],
                d: {
                    hello: "world"
                }
            }
            let serialized = JSON.stringify(complexValue); // serialize
            localStorage.setItem("complexData", serialized);

            let deserialized = JSON.parse(localStorage.getItem("complexData")); // deserialize
            console.log(deserialized);
        }
    </script>
</body>
</html>