Microsoft releases TypeScript 5.5 with ECMAScript set support & performance optimizations

Microsoft has unveiled TypeScript 5.5, the latest iteration of the language designed to enhance JavaScript. Installation is simple through NuGet or npm with the command: npm install -D typescript. Developers using Microsoft Visual Studio or Visual Studio Code for JavaScript already benefit from TypeScript's robust editor tools, such as auto-completion, code navigation, and refactorings.

TypeScript 5.5 brings a host of new features including Inferred Type Predicates, Control Flow Narrowing for Constant Indexed Accesses, the JSDoc @import Tag, and Regular Expression Syntax Checking. It also includes support for new ECMAScript Set Methods, Isolated Declarations, and the ${configDir} Template Variable for configuration files. Other enhancements include consulting package.json dependencies for declaration file generation, improvements in editor and watch-mode reliability, performance and size optimizations, and simplified API consumption from ECMAScript Modules. Additionally, there are changes to the transpileDeclaration API, stricter parsing for decorators, and undefined is no longer a definable type name.

Looking ahead, Microsoft is already developing TypeScript 5.6, with a release expected in early September. Developers can access nightly versions via npm with npm install -D typescript@next, though these builds may contain significant bugs due to limited testing. Detailed nightly documentation is available to assist with setting up TypeScript nightly across various IDEs, including Visual Studio Code, Microsoft Visual Studio, Sublime Text, and IntelliJ IDEA.