Hydration: What is it?

Besides the name, it has nothing to do with water. But still, hydrate yourself. Hydration is simply the process of attaching JavaScript behavior to HTML elements that have been generated on the server, it is necessary to make a web page interactive, allowing users to click buttons, fill out forms, and perform other actions. Without hydration, web pages would be static and unresponsive.

In SSR (Server-side Rendering), the HTML and JavaScript are generated on the server and sent to the client as a fully-formed document. However, this HTML is still just a static representation of the page. Hydration is still necessary to attach event listeners to the page and make it interactive and dynamic. Once the HTML and JavaScript bundles have been downloaded by the browser, the JavaScript takes over and attaches event listeners to the HTML, allowing for a fully interactive user experience.

Hydration isn't needed in client-side rendering (CSR) because the entire JavaScript bundle is loaded and executed on the client, which includes all the necessary event listeners and JavaScript behavior. This means that the JavaScript code can directly manipulate the HTML elements that it created, without the need for hydration. Unlike server-side rendering (SSR), where HTML is generated on the server and sent to the client as a fully-formed document.

Conclusion

Hydration is a key concept in web development, allowing for dynamic and interactive user experiences on the server. By understanding how hydration works in SSR, developers can build web applications that are fast, responsive, and accessible to a wide range of users.