Remove Legacy JavaScript Build Transpilation

How to optimize donnie.cl

Next.js SiteScore: 81/100Analyzed January 2026

Remove Legacy JavaScript Build Transpilation

Medium Impact+8 points estimated

Why It Matters

Legacy polyfills add unnecessary 14 KiB and 150ms LCP delay for modern browsers that don't need them.

How to Fix

Update your Next.js config to target modern browsers by setting 'browserslist' to exclude old browsers. Configure Babel preset-env with 'esmodules: true' to avoid transpiling modern JavaScript features. Use Next.js 13+ automatic modern/legacy build splitting.

0Needs Improvement

What This Score Means

A score of 81 falls in the "Needs Improvement" range (50-89). While it is better than poor (0-49), you should aim for 90+ to provide an optimal user experience and maximize SEO benefits.

This site is slower than approximately 35% of similar sites. The main issues affecting performance are image optimization, JavaScript execution time, and layout stability.

Addressing these issues could improve your conversion rate by 15-20% and boost your search engine rankings.

Core Web Vitals Analysis

LCP

Largest Contentful Paint

4.7s
Poor

Good: < 2.5s

Measures how long it takes for the main content to appear on screen

INP

Interaction to Next Paint

91ms
Good

Good: < 200ms

Measures how quickly the page responds to user interactions

CLS

Cumulative Layout Shift

0.00
Good

Good: < 0.1

Measures visual stability - how much content shifts during page load

AI Performance Analysis

This Next.js site has good performance with a score of 81/100, but has room for significant improvement. The biggest issue is excessive unused JavaScript from Clerk authentication services, which wastes 279 KiB and delays page interactivity to 6.8 seconds - well above the recommended 2.5 seconds. The site's Largest Contentful Paint of 4.7 seconds is also slower than ideal, partially caused by render-blocking CSS files that could save 600ms if optimized. Removing unused JavaScript code, deferring non-critical scripts, and inlining critical CSS would likely boost the performance score into the 90s and dramatically improve user experience.

Other Optimization Recommendations

Reduce Unused Clerk JavaScript Code

High Impact+15 points estimated

Why It Matters:

Unused JavaScript wastes 279 KiB and delays LCP by 450ms, significantly impacting Core Web Vitals.

How to Fix:

Configure Clerk to load only required authentication components using dynamic imports. Implement code splitting in Next.js to defer Clerk loading until authentication is needed. Use Clerk's tree-shaking friendly imports to exclude unused UI components.

Inline Critical CSS Resources

Medium Impact+10 points estimated

Why It Matters:

Render-blocking CSS delays First Contentful Paint by 600ms, preventing users from seeing content quickly.

How to Fix:

Use Next.js built-in CSS optimization to automatically inline critical CSS. Move non-critical styles to load asynchronously using next/dynamic. Consider using CSS-in-JS solutions like styled-components for better code splitting.

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Keep Your Site Fast After Optimization

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