It’s been 6 months since Microsoft released TypeScript 5.1, introducing several new features and performance improvements. One of the new features is allowing undefined-returning functions to have no return statement and inferring undefined for their return type in certain circumstances.

TypeScript 5.1 also supports namespaced attribute names in JSX, a JavaScript extension syntax that allows devs to write HTML and JavaScript together. TypeScript 5.1 provides snippet completions for @param tags in JSDoc comments, which can help developers document their code or add JSDoc types in JavaScript files.