📝 Build a Dynamic Comment Management Interface with Svelte

In this article, we’ll explore how to create a dynamic and interactive interface to manage comments and replies using Svelte. This project demonstrates reusable components, smooth animations, and clean state management practices.

---

🎯 Project Objective

The goal of this project is to build an interface that allows users to:

• Add new comments.
• Edit or delete existing comments.
• Reply to comments.
• Handle errors and provide smooth transitions for a better user experience.

---

📂 File Structure

Here’s the structure of the project files:

src/ ├── App.svelte ├── components/ │ ├── AddComment.svelte │ ├── Comments.svelte │ ├── CommentReply.svelte │ ├── MessageError.svelte

---

🔧 Implementation

1️⃣ Main Component: App.svelte

The App.svelte file manages the central state of the application and orchestrates the interactions between components. Here's a simplified version:

<script>
    import Header from "./components/Header.svelte";
    import Comments from "./components/Comments.svelte";
    import AddComment from "./components/AddComment.svelte";
    import MessageError from "./components/MessageError.svelte";

    let activeFormComment = false;
    let comments = [];
    let error = false;

    function handleAddComment(e) {
        const { username, content } = e.detail;
        if (!username || !content) {
            error = true;
            return;
        }
        comments = [...comments, { id: comments.length + 1, username, content, reply: [] }];
        error = false;
        activeFormComment = false;
    }

    function handleRemoveComment(e) {
        const { commentID } = e.detail;
        comments = comments.filter((c) => c.id !== commentID);
    }
</script>

<Header />
<div class="container">
    <h1>Comment Management</h1>
    {#if error}
        <MessageError message="Please fill out all fields before submitting." />
    {/if}
    <Comments comments={comments} on:removeComment={handleRemoveComment} />
    <AddComment active={activeFormComment} on:submit={handleAddComment} />
</div>

---

### 2️⃣ Add New Comment: AddComment.svelte

This component handles adding new comments with transitions.

import { createEventDispatcher } from "svelte";
export let active = false;
export let reply = false;
let username = "";
let content = "";
const dispatch = createEventDispatcher();

function onSubmit() {
    if (!username || !content) {
        alert("Please fill in all fields.");
        return;
    }
    dispatch("submit", { username, content });
    username = "";
    content = "";
}

{#if active}

Username



Content


Submit

{/if}

---

### 3️⃣ List of Comments: `Comments.svelte`

This component displays the list of comments and their replies.

import { createEventDispatcher } from "svelte";
import CommentReply from "./CommentReply.svelte";
export let comments = [];
const dispatch = createEventDispatcher();

function removeComment(commentID) {
    dispatch("removeComment", { commentID });
}

{#each comments as comment}

{comment.username}: {comment.content}

removeComment(comment.id)}>Delete
{#each comment.reply as reply}

{/each}

{/each}

### 4️⃣ Replies: `CommentReply.svelte`

This component handles the display of replies to comments.

export let comment;



<p><strong>{comment.username}</strong>: {comment.content}</p>

---

5️⃣ Error Handling: `MessageError.svelte`

This component displays error messages.

export let message = "An error occurred.";

{message}

---

## 🎨 Final Result

With this project, you’ll have an intuitive interface where users can:
- Add, edit, delete, or reply to comments.
- See error messages dynamically when required fields are missing.
- Enjoy smooth animations and transitions during interactions.

This interface is lightweight, responsive, and easy to extend, making it a great base for more complex applications or features like comment sorting, pagination, or user authentication.

Here’s a summary of what we’ve built:
1. **Dynamic Comment Management:** Easily manage a list of comments with options to edit, delete, or reply.
2. **Error Feedback:** Inform users about missing fields with a reusable error message component.
3. **Interactive Transitions:** Use Svelte's built-in transitions for a modern and polished user experience.

Feel free to extend this project further by adding:
- **Server Integration:** Connect it to a backend API to persist comments.
- **Authentication:** Restrict certain actions like editing or deleting to authenticated users.
- **Advanced Features:** Add pagination or filtering for comments in large datasets.

Let your creativity guide you !

---

### 🚀 Conclusion

This project showcases how `Svelte `can help you build dynamic and interactive UIs with simplicity and efficiency. Features like built-in animations and state management make Svelte an excellent choice for modern web applications.