JavaScript to TypeScript Migration Best Practices Guide for taking a JavaScript codebase to strict, modern TypeScript without a big-bang rewrite. Contains 42 rules across 7 categories, prioritized by impact to drive an incremental, file-by-file migration that keeps the build compiling at every step. When to Apply Reference these guidelines when: - Converting a codebase to (whole project or one module at a time) - Adding types to existing JavaScript via JSDoc or annotations - Choosing a and strategy for a mixed JS/TS repo - Turning on mode or individual strict flags on a large codebase - Repla…