Optimize JavaScript Execution Performance

How to optimize learn.wowlearnings.org

Next.js SiteScore: 64/100Analyzed May 2026Re-analyze this site

Optimize JavaScript Execution Performance

High Impact+12 points estimated

Why It Matters

JavaScript execution takes 2.3 seconds and causes 750ms of Total Blocking Time, preventing user interactions.

How to Fix

Split large JavaScript bundles using Next.js automatic code splitting. Move heavy computations to Web Workers. Update your build configuration to target modern browsers and remove unnecessary polyfills for Array.from, Object.hasOwn, and other baseline features.

0Needs Improvement

What This Score Means

A score of 64 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

3.8s
Needs Improvement

Good: < 2.5s

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

INP

Interaction to Next Paint

397ms
Needs Improvement

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 poor performance with a score of 64/100, indicating significant user experience issues. The biggest problem is excessive unused JavaScript (285 KiB wasted), which is severely slowing down page loading and causing an 8.4-second Speed Index - meaning visitors wait over 8 seconds to see meaningful content. The site is also suffering from render-blocking CSS files and inefficient JavaScript execution that's monopolizing the main thread for over 4 seconds. Removing unused JavaScript code, optimizing the build process to eliminate unnecessary polyfills for modern browsers, and addressing the render-blocking resources could dramatically improve loading speeds and user satisfaction.

Other Optimization Recommendations

Eliminate Render Blocking Resources

High Impact+18 points estimated

Why It Matters:

CSS files are blocking initial page render and delaying both LCP and FCP by 500ms.

How to Fix:

Move critical CSS inline in your Next.js _document.js file. Use next/dynamic with ssr: false for non-critical components. Implement CSS code splitting by moving unused styles to component-specific CSS modules.

Remove Unused JavaScript Code

High Impact+15 points estimated

Why It Matters:

285 KiB of unused JavaScript is delaying LCP by 450ms and blocking the main thread.

How to Fix:

Use Next.js bundle analyzer to identify unused code. Implement dynamic imports for heavy components that aren't immediately visible. Remove or defer Google Analytics until after page load using next/script with strategy='afterInteractive'.

Keep Your Site Fast After Optimization

Once your site is optimized, maintain that speed. Use DeployHQ for zero-downtime, automated deployments—so performance fixes and updates go live safely every time, without breaking your site.

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