To efficiently manage the read/unread status of items using localStorage as the persistent data store, you must serialize the (un)read state into a string format for storage and then deserialize it upon retrieval since localStorage only supports string values. JSON serves as an optimal choice for serialization due to its ability to represent various JavaScript data structures and simple parse/stringify capabilities.
It can be challenging to demonstrate such functionality in a live code snippet on platforms like Stack Overflow due to restricted access to features like localStorage, which triggers runtime exceptions when attempted. However...
Below is a self-contained demonstration illustrating the storage of read/unread states for a list of items through basic functional programming techniques for organized code structure. This example comprises plain HTML + CSS + JavaScript without any external frameworks like React. You can easily copy + paste this code into a local HTML file on your computer and run it using a local static file server (e.g., Deno or Python) to witness its functionality. Detailed comments are included throughout to guide you through each step of the program execution.
If you wish to inspect the state of your localStorage during testing, refer to the question How to view or edit localStorage?.
<!doctype html>
<html lang="en">
<head>
<meta charset="utf-8" />
<meta name="viewport" content="width=device-width, initial-scale=1" />
<title>LocalStorage: read/unread items</title>
<style>
/* Sample styles for illustration purposes - styling customization can be applied */
* { box-sizing: border-box; }
body { font-family: sans-serif; }
.toggle-status {
font-size: 1rem;
padding: 0.25rem;
width: 8rem;
}
#list {
list-style: none;
padding: 0;
display: flex;
flex-direction: column;
gap: 0.5rem;
align-items: flex-start;
}
.item {
display: flex;
gap: 1rem;
align-items: center;
}
.item.read > .item-content { font-weight: normal; }
.item.unread > .item-content { font-weight: bold; }
</style>
<script type="module">
// Functions to handle read/unread item states stored in localStorage
// Ensure proper storage and retrieval of read/unread item states
// Update the read/unread status for a single item
// Toggle between read/unread status for an item
// Invocation function
</script>
</head>
<body>
<!--
List of items with unique IDs, toggle buttons,
and text contents
-->
<ul id="list">
<li class="item" data-id="cc9e88ce-3ed4-443a-84fc-fa7147baa025">
<button class="toggle-status">Mark as read</button>
<div class="item-content">First item content</div>
</li>
<li class="item" data-id="23a9204c-905f-48db-9f6a-deb3c8f82916">
<button class="toggle-status">Mark as read</button>
<div class="item-content">Second item content</div>
</li>
<li class="item" data-id="18b47e4c-635f-49c0-924e-b9088538d08a">
<button class="toggle-status">Mark as read</button>
<div class="item-content">Third item content</div>
</li>
<li class="item" data-id="ed2aacca-64f0-409d-8c1b-d1bdcb7c6058">
<button class="toggle-status">Mark as read</button>
<div class="item-content">Fourth item content</div>
</li>
<li class="item" data-id="0fce307b-656a-4102-9dc9-5e5be17b068d">
<button class="toggle-status">Mark as read</button>
<div class="item-content">Fifth item content</div>
</li>
<!-- ...etc. -->
</ul>
</body>
</html>