What is the difference between Layout and Template in NextJS

Dive deep into the realms of NextJS, emphasizing the inherent differences between layout and template in terms of state preservation and data reassembly.

Introduction to layout in NextJS

A layout in NextJS facilitates the consistent implementation of repetitive UI elements across multiple pages. Simply put, it's a higher-level component that wraps around a page. In terms of state preservation, the layout plays a crucial role - it preserves the state during navigation, avoiding the need to recreate it. Let's encapsulate this concept in some code. Consider a simple layout that wraps around the child support:

export default function Layout({
                                 children,
                               }: {
  children: React.ReactNode;
}) {
  return <div>
    <Header/>
    {children}
    <Footer/>
  </div>;
}

In this component, the header and footer are maintained as static elements. In addition, when navigating between different pages using this layout, any state stored within this structure remains intact. This provides a seamless user experience, which is particularly useful when working with input that retains user data even during navigation.

Deepening the template in NextJS

Conversely, a template in NextJS is essentially a grounding structure for pages, reflecting common properties without imposing them. Templates reassemble during navigation, meaning that they recreate DOM elements, resetting React's client state along with any intertwined effects each time we navigate.
Here's a basic template application to help you understand:

export default function Template({
                                 children,
                               }: {
  children: React.ReactNode;
}) {
  return <div>
    <Header/>
    {children}
    <Footer/>
  </div>;
}

This template outlines the structure of the pages. But it's important to remember that the entire template is re-rendered during navigation, resetting any client state or browser form input within it like in header search bar state, etc.

Summary

In NextJS, both layout and template may appear to be similar constructs. However, they play different roles when it comes to state handling and component lifecycles. While Layout ensures a persistent state across navigations, Template resets and renders, discarding any accumulated state from previous navigations. Understanding these nuances is essential to creating efficient and user-friendly NextJS applications.

Happy templating!