Understanding Template Files in Next.js The Complete Guide

Next.js 15 introduces the template file, a counterpart to layout, offering granular control over layout behavior during navigation. This guide clarifies the distinctions between template and layout, outlining their applications and best practices.

---

Understanding Template Files

A Next.js template file defines reusable layouts that refresh their state or re-render upon page transitions. This differs from layout, which preserves state across transitions.

---

Template vs. Layout: A Comparison

Feature	Layout	Template
State Persistence	Retains state during route changes.	Resets state on each route change.
Reusability	Provides consistent layouts across pages.	Similar to `layout`, but ensures fresh rendering for every page.
Use Cases	Ideal for persistent elements like headers, sidebars, or footers.	Suitable for layouts needing resets or re-initialization per route, such as forms or dynamic content.
Rendering	Doesn't re-render between sibling routes.	Re-renders with every route change.

---

Choosing Between Template and Layout

Use template when:

• State resets or re-initialization are required during navigation.
• Forms or inputs within the layout need value resets.
• Content is highly dynamic and must reflect route-specific changes.

Use layout when:

• A persistent structure, like a navigation bar or footer, is needed.
• Layout components are static or don't require frequent re-initialization.

---

Illustrative Example: Input Reset Behavior

This example highlights the layout and template differences.

Using layout (State Persists):

<code>// app/layout.tsx
import './globals.css';

export default function RootLayout({ children }: { children: React.ReactNode }) {
  return (
    
      
        <p>Header Content</p>
        {children}
      
    
  );
}</code>

• Here, input field values persist across routes because the layout doesn't re-render.

Using template (State Resets):

<code>// app/template.tsx
import './globals.css';

export default function RootTemplate({ children }: { children: React.ReactNode }) {
  return (
    
      
        <p>Header Content</p>
        {children}
      
    
  );
}</code>

• Input values reset on each route change due to the template's forced re-render.

---

Dynamic Content Handling with Template

template excels at managing dynamic content. In an e-commerce app, a template file ensures filter or search input resets when navigating between product categories.

Example: Dynamic Product Filtering

<code>// app/shop/template.tsx
export default function ShopTemplate({ children }: { children: React.ReactNode }) {
  return (
    <main><h1 id="Shop">Shop</h1>
      {children}
    </main>
  );
}</code>

The search input resets with each category change, providing a clean user experience.

---

Best Practices

1. Assess State Needs: Use layout for persistent state (navigation, authentication); use template for resetting state-sensitive components (forms, dynamic filters).

2. Avoid Overuse of Templates: template is valuable, but overuse leads to unnecessary re-renders. Favor layout for static or less-dynamic components.

3. Prioritize Performance: Keep templates concise, avoiding complex computations or large components.

4. Test Navigation: Verify that your layout/template choice aligns with the user experience, especially for interactive elements like forms or modals.

---

Conclusion

Understanding the distinction between layout and template in Next.js 15 is crucial for building efficient and user-friendly applications. layout provides persistence and stability, while template offers flexibility for state resets and dynamic re-renders. Effective use of both features results in performant and intuitive applications.

---

Let's connect on LinkedIn or GitHub ?

The above is the detailed content of Understanding Template Files in Next.js The Complete Guide. For more information, please follow other related articles on the PHP Chinese website!