TypeScript 5

TypeScript 5 delivers a leaner, faster compiler with native support for ECMAScript Decorators and improved type inference.

Version 5.0 rearchitects the compiler for efficiency: it cuts the package size by 26 MB (a 40% reduction) and boosts build speeds via a move to ES modules. Developers gain access to the finalized ECMAScript Decorators standard, 'const' type parameters for literal inference, and support for multiple 'extends' in tsconfig.json. These refinements prioritize performance for enterprise scale JavaScript development.

https://www.typescriptlang.org/docs/handbook/release-notes/typescript-5-0.html