Next.js 9.1.7

Summary

Next.js 9.1.7 delivers significant performance improvements and developer experience enhancements while maintaining full backward compatibility. This release focuses on optimizing bundle sizes, improving page loading performance, and adding modern JavaScript feature support.

Key Points

• Bundle Size Reduction: 3-8% smaller client-side JavaScript with 7.5kB+ savings through optimized JSX output and built-in polyfills
• Built-in Polyfills: Native support for fetch(), URL, and Object.assign with differential loading (eliminates up to 18kB on modern browsers)
• Enhanced Build Output: Redesigned CLI with gzipped file sizes, page classification (Server/Static/SSG), and performance color coding
• Page Loading Optimization: Improved FCP and TTI through better CSS prioritization and optimized prefetching during browser idle-time
• Modern JavaScript Support: Added Optional Chaining (?.) and Nullish Coalescing (??) operators with automatic browser compatibility
• React Strict Mode: Full compliance across Next.js runtime with opt-in configuration support
• Zero-Config Deployment: next export applications now work with Vercel out-of-the-box
• Quality Assurance: Automated testing against React nightly builds ensures future compatibility