Flags as Code in Next.js

What this post added

Introduces the new Flags SDK for Next.js and SvelteKit, which acts as an abstraction layer between applications and feature flag providers. It emphasizes server-side evaluation, the concept of feature flags as functions, and the inability to pass arguments on the call side to ensure consistent flag resolution and simplify migration and deletion. The post details basic flag declaration, progressions of usage with tradeoffs (hardcoded values vs. redeployments), and integration with the Vercel Toolbar for overrides. It also touches upon precomputing flags for static pages and using Edge Middleware for routing.