Why is there a need for another framework? the current approach is not producing fast sites, and this problem will not disappear by waiting for a faster CPU.

Foreword

Qwik in Action

Introduction to the frontend development. Now, the responsibility of creating good or bad applications depends on you because the means available are all there.

Introduction

Overview of TypeScript. TypeScript introduced types into an untyped language like Javascript to ensure code consistency.

TypeScript

Overview of the frontend architectures. In this lesson you will understand the difference from Client Side Rendering and Multi Page Application.

Frontend architectures

Overview of the hydration. In this lesson you will understand the difference from Hydration and Island architecture/Partial Hydration.

Hydration

React Server Component. In this lesson you will understand the difference from Server Component and Client Component.

React Server Component

Qwik resumability will change the frontend ecosystem, In this lesson you will understand why is so great.

Resumability, the Qwik way

Wrap up of frontend architectures module.

Summary Chapter 2

In this lesson you will be able to understand more about performance and you will understand how improve your application with less JavaScript.

Qwik, the framework built on top of closure-extraction

Resumability is the core concept behind Qwik. In this lesson you will understand better the process.

Resumability

Code Extraction is a topic hard to master, you will understand how it works with different approaches.

Code Extraction

JSX syntax is the most famous one because of React, but what about the other frameworks, Vue, Angular?

Why Qwik use JSX syntax

Summary Chapter 3

Let's see together the fundamentals of Qwik. In this lesson you will compare Webpack and Vite.

Getting started with Qwik

The Qwik build process is so important because the resumability process requires correct and intelligent bundling.

Qwik compilation Process

Qwik CLI and amazing tool to have a great Developer Experience with Qwik.

Technical requirements to start a new Qwik application

Qwik Middleware an easy and clever way to expose your RESTful APIs or GraphQL APIs.

Middleware

Wrap up of Getting Started with Qwik module.

Summary Chapter 4

In this lesson you will learn the pillars of SEO. You will lean few new terms and metrics that can help you to measure your application.

In this lesson you will learn the some new things about SEO and crawler.

Sitemap and robots files

Partytown an amazing library to execute third scripts in the service worker.

Partytown

Core Web Vitals are so important for own application. You will learn in detail all the metrics.

Core Web Vitals

Core Web Vitals Labs Data vs Field Data. These two information are so different, let's figure out the peculiarity of those.

Labs data vs Field data

Summary Chapter 5

SEO and Core Web Vitals

There are many ways to deploy a Qwik application. You can have your own server and deploy your Qwik application easily with the Qwik CLI and integrations.

Deploy Qwik in production

Cloud solution are a good alternative for a low cost pipeline and host. Nowadays these kind of services are so smart and great, you should try them.

Cloud solutions

With different team and many developers, it's important to master branching strategies to avoid problems during your day by day.

Branching strategies

Progressive Web App approach can be an alternative to the stores. You can publish you application with a lot of benefit with PWA.

Progressive Web App

Wrap up of Deploy Qwik in Production module.

Summary Chapter 6

Style an application is so important let's see how engage your Stakeholders into this process.

Style and render data with Qwik

CSS is so huge, there are a lot of ways to style your application with Qwik, let's see them together.

CSS and Built-In Styling Methods

Tailwind is an amazing library, let's see together how master it. I will share you some tips and tricks to use Tailwind in a better way.

Tailwind CSS

In this lesson you will learn how manage data with Qwik. There are a lot of APIs to explore, let's jump into the code.

Managing data with Qwik

Summary Chapter 7

In this lesson you will learn how architect a modern frontend end application.

Creating an e-commerce with Qwik and Supabase

In this lesson you will learn the trade offs of technical decisions. I share with you some tips and tricks.

Technological spike

In this lesson you will explore Supabase. This is an amazing service to leverage your business.

Supabase for your backend

A custom authentication is too complex and risky to implement from scratch. Let's use the Supabase auth to optimize our goals.

Let's talk about the Authentication process

Summary Chapter 8

Supabase CLI an handy tool to improve consistency across environments.

Supabase CLI

Let's use the Supabase CLI to manage our database migrations and schemas.

Supabase db migrations

In this lesson you will create the e-commerce homepage with the Supabase client to read the data.

Show products on our homepage

Every e-commerce has a detail page, let's create our product detail page with Qwik.

Product Detail

Cache is really useful and in this lesson I will explain in the detail how it works. I will share my experience in this topic with some cool analogies.

Cache-control headers

Summary Chapter 9

Rendering products with Orama full text search

Let's improve out application with a useful "Add to favorites" feature.

Add a product to your favorites list

In this lesson you will learn how to use Stripe to manage your payments in a secure way.

Adding cart and checkout process with Stripe

Let's try the Supabase database function. This is an easy way to allows us to do several things and also add some logic to our procedure.

Page views tracking

A real-time database with Supabase is so simple to implement, let's build together a new functionality with this great feature.

Real-time database

Summary Chapter 10

Let's explore together the benefit of testing. In this lesson you will explore the various types of tests, Unit Test, E2E, Visual regression tests and more.

Overview of application testing

Let's discuss together how and when testing is valuable for our business. 3X Explore/Expand/Extract can help us is this reasoning.

How much testing is enough? When do I write tests?

In this lesson you will lean the Test driven development TDD flow. It's a really good practice to put in place.

Test-Driven Development (TDD)

In this lesson you will lean how test your components with Cypress.

Let's add some tests with Cypress

Do you need a Qwik component library? Qwik UI is the project for you because can give you a lot of Qwik accessible components out of the box.

Qwik UI

Summary Chapter 11

Adding tests to our Qwik application

Let's explore a bit of history of Qwik. A new framework with a great past.

Final thoughts

Qwik and React together, no problem, qwikify$ is the API to solve your problems.

qwikify$

Qwik and Astro together, no problem, @qwikdev/astro is the library to solve your problems.

Qwik inside Astro application

Qwik and micro-frontends together, no problem, out of the box Qwik can manage this scenario with no external dependencies.

Micro-frontends with Qwik

Summary chapter 12

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( the primaryDescriptionMarkdown is long - several lines, include images, as long as you want )

In this course we <headline of what we do>. <why this technology is good> but <here's how learning it is problem>. 

In <the length of these lessons> we cover <three salient points about what we cover. Your BEST points>. Its <however long it is> and comes with <these bonus features, and reasons to buy. code, etc.>

It's taught by <author name> who <credibility, reason you should listen to them>. <social proof, if you have it yet>

<then you can list other supporting stuff you want to add, anything you want here>

-------
Example:
-------

We created a free course to create your first GraphQL server (from scratch) using Node and TypeScript. TypeScript and GraphQL are a powerful combo, but there's a lot of confusing edges if you're getting it setup the first time.

In this course we cover the basics of getting TypeScript setup with Node, how GraphQL works, and how to set up a GraphQL server using Apollo server. It's two hours long, it comes with complete code examples, and we walk through the code step-by-step.

It's taught by my friend, Shopify-engineer Hassan Djirdeh and he's integrated what he's learned using GraphQL in production as an engineer at Shopify. We've already had over 1,300 students enroll and it's been getting great reviews so far.

// ... and so on

Harness Qwik Resumable Architecture for Lightning-Fast Startup Times

In this course we <headline of what we do>. <why this technology is good> but <here's how learning it is problem>. 

( the summary is short - one or two lines )

Complete Guide to Qwik

Hydration is a process that occurs on the client side and is linked to the generation of pages on the server side. It is used to recreate the state of the application (e.g., the state of the open/closed menu) and the interactivity of the HTML rendered by the server (e.g., the listener of events on the buttons to make them interactive). The server generates the page server-side to support SEO and sends this page in HTML and CSS to the browser. Then, an additional process, Hydration, is needed to add the application state.

To carry out the Hydration process, all input information is needed, such as the data displayed on the page rather than the number of open orders that need to be processed. This type of behavior is easy to notice because, in the Network tab of the browser, data being sent from the server to the client can be seen to ensure this mechanism. This creates network overhead just to perform this state reconciliation process, which is a problem and a waste of resources.

Imagine a header with the title of the page and a button that opens and closes the side menu. The page sent from the server to the browser will contain the page's title and the menu's state, which will be used by the application to show whether the menu is open or closed. This gives a significant advantage for SEO. However, once the page is rendered, it will begin the hydration process, which will calculate the state of the menu and attach the listener to the menu button to allow the application to become interactive.

Here, the hydration rendering process can be seen.

Note that JavaScript is used twice, once to create the HTML and the other to perform the Hydration. If the word "My Shop" is searched within the files produced by the build, this word will be found twice in the HTML and JavaScript sent to the browser because all the information is used to recreate the state. So, the process seems faster than a single-page application because there is faster feedback, but more time passes before interaction with the app is possible, and therefore, in the end, it's slower.

However, the end users of the application are now able to see and read the contents even if they are not completely interactive because, as mentioned, server-side rendering eliminates the problem of the blank page at startup (typical of the CSR approach) and this is all to the advantage of search engines and social media crawlers. It is possible to add some extra information to the static page sent by the server, which allows the links to preview the contents. So, imagine sending a link to an article that has been read to an acquaintance; this link, referring to a page containing this extra information, will be displayed with a preview of the article itself to offer a superior user experience.

To overcome the costly waste of resources that hydration causes, a solution was sought by splitting and postponing the hydration process; this architecture is also called Partial hydration.
The central point of this architecture is the concept of an island because the HTML pages will be rendered on the server, and only in the points where there is dynamism will an island be defined.

There can be multiple islands within the same page; these islands are like placeholders, which will then be hydrated on the client side independently, thanks to the HTML and the state that the server provides.
So, in fact, the Hydration problem is being circumvented only by splitting the process into multiple independent operations.

In general, the applications that benefit from this approach are mostly static, with some points where there is dynamism; blogs, news sites, and showcase sites are the ideal use cases for this architecture because, all in all, it does not bring disadvantages.
By doing this, the static content does not require rework because it does not support events, but for example, the buttons, search bar, and menu must receive special treatment to become interactive and require the input state provided by the server for rehydration and event management.

This is just an example, but to get good results we need to think about how to split our app.
Here, through the appropriate APIs, some frameworks allow us to render our HTML page without interactivity and to intelligently hydrate only parts of our page. Let's imagine we have a part of the page outside the initial viewport, for this section, it is possible to define an island and postpone the hydration process until it is visible. 

 for example, one of the frameworks that supports the Island architecture, offers us various directives to command Hydration at a time we see fit.

 in that it loads, renders, and hydrates the component immediately on page load.

In the previous graph, we can see that the islands are independent silos and the borderline is clear and well delineated, but once we have all these islands on our page we will also have to share some information between islands. For example, let's think about wanting to select one or more orders from a list, and in the header we want to display the sum of all the selected orders. If to optimize the rendering we have separated these two components into islands we must find a way to make them communicate. If we want to co-share the state between islands, the solution that is used as a standard is to share the information via a state external to the islands. In this way, the external source will act as a source of truth to keep the information, but in my opinion, it is not an optimal solution. The first problem I see is that we have to use an external library to manage the state, as a second thing we are adding a layer and further boilerplate code for such a simple and certainly necessary operation in most applications.
So in my opinion this architecture tries to solve the hydration problem but introduces other limitations which then fall on the shoulders of the developers who have to fight these problems.

---
title: Hydration
description: Overview of the hydration. In this lesson you will understand the difference from Hydration and Island architecture/Partial Hydration.
---

# Hydration

Hydration is a process that occurs on the client side and is linked to the generation of pages on the server side. It is used to recreate the state of the application (e.g., the state of the open/closed menu) and the interactivity of the HTML rendered by the server (e.g., the listener of events on the buttons to make them interactive). The server generates the page server-side to support SEO and sends this page in HTML and CSS to the browser. Then, an additional process, Hydration, is needed to add the application state.

To carry out the Hydration process, all input information is needed, such as the data displayed on the page rather than the number of open orders that need to be processed. This type of behavior is easy to notice because, in the Network tab of the browser, data being sent from the server to the client can be seen to ensure this mechanism. This creates network overhead just to perform this state reconciliation process, which is a problem and a waste of resources.

Imagine a header with the title of the page and a button that opens and closes the side menu. The page sent from the server to the browser will contain the page's title and the menu's state, which will be used by the application to show whether the menu is open or closed. This gives a significant advantage for SEO. However, once the page is rendered, it will begin the hydration process, which will calculate the state of the menu and attach the listener to the menu button to allow the application to become interactive.

Here, the hydration rendering process can be seen.

![Hydration](https://d2uusema5elisf.cloudfront.net/courses/complete-guide-to-qwik/module_02/lesson_02.04/public/assets/Hydration.png)

Steps:

-   Immediately download the HTML with the information to show a snapshot of the application. It is larger than the one previously seen in the Single Page Application.
-   Then, download the JavaScript needed to perform the hydration process.
-   Run the application.
-   There is the Reconciliation phase, which recreates the state.
-   Finally, the application is interactive, and it can be clicked.

Note that JavaScript is used twice, once to create the HTML and the other to perform the Hydration. If the word "My Shop" is searched within the files produced by the build, this word will be found twice in the HTML and JavaScript sent to the browser because all the information is used to recreate the state. So, the process seems faster than a single-page application because there is faster feedback, but more time passes before interaction with the app is possible, and therefore, in the end, it's slower.

However, the end users of the application are now able to see and read the contents even if they are not completely interactive because, as mentioned, server-side rendering eliminates the problem of the blank page at startup (typical of the CSR approach) and this is all to the advantage of search engines and social media crawlers. It is possible to add some extra information to the static page sent by the server, which allows the links to preview the contents. So, imagine sending a link to an article that has been read to an acquaintance; this link, referring to a page containing this extra information, will be displayed with a preview of the article itself to offer a superior user experience.

![link_with_preview](https://d2uusema5elisf.cloudfront.net/courses/complete-guide-to-qwik/module_02/lesson_02.04/public/assets/link_with_preview.png)

## Island architecture

To overcome the costly waste of resources that hydration causes, a solution was sought by splitting and postponing the hydration process; this architecture is also called Partial hydration.
The central point of this architecture is the concept of an island because the HTML pages will be rendered on the server, and only in the points where there is dynamism will an island be defined.

There can be multiple islands within the same page; these islands are like placeholders, which will then be hydrated on the client side independently, thanks to the HTML and the state that the server provides.
So, in fact, the Hydration problem is being circumvented only by splitting the process into multiple independent operations.

In general, the applications that benefit from this approach are mostly static, with some points where there is dynamism; blogs, news sites, and showcase sites are the ideal use cases for this architecture because, all in all, it does not bring disadvantages.
By doing this, the static content does not require rework because it does not support events, but for example, the buttons, search bar, and menu must receive special treatment to become interactive and require the input state provided by the server for rehydration and event management.

![island_architecture](https://d2uusema5elisf.cloudfront.net/courses/complete-guide-to-qwik/module_02/lesson_02.04/public/assets/island_architecture.png)

This is just an example, but to get good results we need to think about how to split our app.
Here, through the appropriate APIs, some frameworks allow us to render our HTML page without interactivity and to intelligently hydrate only parts of our page. Let's imagine we have a part of the page outside the initial viewport, for this section, it is possible to define an island and postpone the hydration process until it is visible. [Astro](https://astro.build/) for example, one of the frameworks that supports the Island architecture, offers us various directives to command Hydration at a time we see fit.

Example:

```typescript
<BuyButton client:load />
```

-   **client:load**: Based on priority, as soon as possible.
-   **client:idle**: According to priority, calmly.
-   **client:visible**: Based on whether they are visible or not.
-   **client:media**: Based on screen size.
-   **client:only**: Skip HTML server rendering and render only on the client.

> `client:only` is similar to `client:load` in that it loads, renders, and hydrates the component immediately on page load.

In the previous graph, we can see that the islands are independent silos and the borderline is clear and well delineated, but once we have all these islands on our page we will also have to share some information between islands. For example, let's think about wanting to select one or more orders from a list, and in the header we want to display the sum of all the selected orders. If to optimize the rendering we have separated these two components into islands we must find a way to make them communicate. If we want to co-share the state between islands, the solution that is used as a standard is to share the information via a state external to the islands. In this way, the external source will act as a source of truth to keep the information, but in my opinion, it is not an optimal solution. The first problem I see is that we have to use an external library to manage the state, as a second thing we are adding a layer and further boilerplate code for such a simple and certainly necessary operation in most applications.
So in my opinion this architecture tries to solve the hydration problem but introduces other limitations which then fall on the shoulders of the developers who have to fight these problems.


Hydration

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