What are we going to build? During this lesson, you'll get to know more about the course, the tech stack, and what you're going to learn.

Course Introduction

Introduction

In this lesson, we'll cover the basics of GraphQL; what it is and how to use it. We'll also understand how it fits the course's subject.

Introduction to GraphQL

We'll learn about Hasura and play a bit with its features and writing GraphQL queries. This knowledge will let us move on to the commenting system!

Using Hasura to Generate GraphQL APIs and Protect Data

In this lesson, we'll create a comments table and learn a bit about databases along the way.

How to Create a Comments Database Table and Set Permissions

Storing comments with Hasura

We'll get to know a sample blog application that we'll be adding a comments section to. We'll also go over the setup and explain the directory structure.

Setting Up Next.js Blog Starter and Understanding Its Structure

In this lesson, we'll create a React hook that will fetch the comments from the database. We'll cover how to create a custom hook as well as how to integrate with Hasura.

Fetching Blog Comments from a Database with a Custom React Hook

In this lesson, we'll add a UI for the comments section and a new comment form. We'll also display the comments that we get from the React hook.

A Brief Tutorial on Building the UI for a Blog Comments Section

This lesson will show how to extend the hook to handle adding new comment logic. It will cover adding a new GraphQL mutation and using it from the frontend application.

How to Use GraphQL to Add Comment Features to a Frontend App

Implementing a comments system

We'll learn about optimistic updates and add them to our hook's implementation to improve the user experience.

An Overview of Optimistic Updates for React Hooks

In this lesson, we'll add pagination to both the hook and UI.

Adding Pagination to a Comments Section with Hasura and React

Extending the comments system functionality

This lesson will teach you how to publish a React hook as an NPM library.

How to Publish a Custom React Hook as an NPM Library

Right now, all the comments are public instantly. However, we may want to review the comments before showing them to other users. This is what we'll cover in this lesson.

Coding a Comments Section that Requires Manual Content Approval

Bonus

We just completed the course! Let's see what's next and how you can use the new knowledge.

Summary

react

next.js

### The newline Guide to Full Stack Comments with Hasura and React

Build and implement a comprehensive commenting system for your website using Hasura and React.  We’ll use the commenting feature to teach technology concepts like Hasura with appropriate authorization, optimistic updates for a more responsive UI, pagination, and publication of library in NPM.

### Why this course

Many developers would like to add a comments section to their website or blog for users to post comments or hold discussions. While it's possible to use existing hosted solutions such as Disqus or Facebook Comments, they often charge a fee and impose their UI leaving little to no control for modifications or customization. 

Another option is to build your own from scratch — which is what we'll do in this course. We’ll use Hasura, which generates GraphQL API from a database so that the backend part is as easy and the least time-consuming as possible. Along the way, we’re going to learn about databases, GraphQL, building UI components with React and TypeScript, and more.
By the end of this course, you’ll have a commenting system added to a website we’ve called, Why comments?, with all comments stored by Hasura. We'll also publish the fetching and adding comments logic as a library to NPM.

This course focuses on building a commenting widget, however, the skills you’ll acquire will allow you to build any fullstack widget you can think up for your application.  You’ll be able to contribute to fullstack React, GraphQL, and Hasura projects at work, in open source, or your own projects. You'll discover that this stack not only eliminates the need for having large teams of backend developers, but it lets your projects move faster.

### Your Instructors

Hi, I'm Aleksandra, and I'm your instructor for this course. I’m the former tech lead of Hasura console and lead maintainer of Bliz.js. This course combines my knowledge in a few areas such as TypeScript, React, Hasura, GraphQL, and general application development.

Build and implement a comprehensive commenting system for your website using Hasura and React.  We’ll use the commenting feature to teach technology concepts like Hasura with appropriate authorization, optimistic updates for a more responsive UI, pagination, and publication of library in NPM.

The newline Guide to Full Stack Comments with Hasura and React

Implementing pagination and optimistic updates

Importance of tests, and how to test React components

In the previous module, we implemented the 

 hook, we tested it, and
we saw that it works as expected. However, every time a user adds a comment, we
refetch all the comments from the database. We're making two API requests:

The latter seems redundant as we already have all the information about the new
comment that we need. Also, making an additional call puts the comments section
into a loading state. For blog posts with many comments, the page may feel slow.
Hence it's not the best user experience.

Wouldn't it be enough to push it to the comments state as we have all the
information? The push is not enough, because we need to handle the 


mutation error, but we can improve our hook and enhance the experience. That's
what we're going to do in this lesson!

In an optimistic update, the UI assumes that the change was successful and
displays the new state before receiving information from the API. When API
returns a confirmation that the call was successful, the UI stays the same. We
don't have to do anything unless API gives some additional info. If there was an
error, we need to handle it on the frontend and revert the change.

Let's go back to the code editor and open the 

export interface Comment {
  author: string;
  content: string;
  created_at: string;
  topic: string;
  status: "adding" | "added" | "failed";
}

---
title: An Overview of Optimistic Updates for React Hooks
privateVideoUrl: https://fullstack.wistia.com/medias/d5a175tmx8
isPublicLesson: false
description:
  We'll learn about optimistic updates and add them to our hook's implementation
  to improve the user experience.
useMdx: true
---

In the previous module, we implemented the `useComments` hook, we tested it, and
we saw that it works as expected. However, every time a user adds a comment, we
refetch all the comments from the database. We're making two API requests:

-   add comment mutation
-   fetch comments

The latter seems redundant as we already have all the information about the new
comment that we need. Also, making an additional call puts the comments section
into a loading state. For blog posts with many comments, the page may feel slow.
Hence it's not the best user experience.

Wouldn't it be enough to push it to the comments state as we have all the
information? The push is not enough, because we need to handle the `AddComment`
mutation error, but we can improve our hook and enhance the experience. That's
what we're going to do in this lesson!

### Introducing optimistic updates

In an optimistic update, the UI assumes that the change was successful and
displays the new state before receiving information from the API. When API
returns a confirmation that the call was successful, the UI stays the same. We
don't have to do anything unless API gives some additional info. If there was an
error, we need to handle it on the frontend and revert the change.