TypeScript 5.5 introduces several new features and enhancements including inferred type predicates, control flow narrowing for constant indexed accesses, the JSDoc @import tag for type-checking in JavaScript files, regular expression syntax checking, and support for new ECMAScript Set methods. Additionally, improvements have been made in performance, API consumption from ECMAScript modules, and declaration file generation. The update also includes notable behavioral changes and continued efforts towards optimizing the development experience.
Table of contents
What’s New Since the Beta and RC?Inferred Type PredicatesControl Flow Narrowing for Constant Indexed AccessesThe JSDoc @import TagRegular Expression Syntax CheckingSupport for New ECMAScript Set MethodsIsolated DeclarationsThe ${configDir} Template Variable for Configuration FilesConsulting package.json Dependencies for Declaration File GenerationEditor and Watch-Mode Reliability ImprovementsPerformance and Size OptimizationsEasier API Consumption from ECMAScript ModulesThe transpileDeclaration APINotable Behavioral ChangesWhat’s Next?1 Comment
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