Why JavaScript Performance Matters
JavaScript is often the biggest contributor to slow page load times. It blocks the main thread, delays interactivity, and can significantly impact Core Web Vitals like INP and TBT.
JavaScript Optimization Techniques
1
Analyze Your Bundle
Use bundle analyzers like webpack-bundle-analyzer to identify large dependencies and unused code.
2
Implement Code Splitting
Split your bundle into smaller chunks that load on demand using dynamic imports.
3
Enable Tree Shaking
Ensure your build tool removes unused exports. Use ES modules for better tree shaking.
4
Use defer and async
Add defer to non-critical scripts. Use async for independent scripts like analytics.
5
Minimize Third-Party Scripts
Audit third-party scripts. Remove unused ones and self-host critical scripts when possible.