TypeScript 3.1 Released

Microsoft recently announced the release of TypeScript 3.1, an open source programming language built on top of JavaScript and adds static type-checking. It is designed for development of large applications and transcompiles those to JavaScript.

The update has Mappable tuple and array types that are said to be one of the most common patterns in programming. “TypeScript is now better-equipped to express functions similar to Promise.all. While that specific change hasn’t made its way into this release, it may be coming in the near future.” stated the Microsoft about the functionality of the feature.
TypeScript 3.1 is offering easier properties on function declarations, developers can have their container scope with type-checker to track any added properties. It's also offering support towards JSX.LibraryManagedAttributes, facilitating migration of untyped React Codebase to TypeScript.
Stating the fact that the release redirects TypeScript via typesVersions, Microsoft further stated, “when using Node module resolution in TypeScript 3.1, when TypeScript cracks open a package.json file to figure out which files it needs to read, it first looks at a new field called typeVersions.

A few breaking changes have also been mentioned in the announcement like the removal of vendor-specific declarations and a slight difference in narrow functions.

You can refer to the Roadmap to know more about the new version or read the full official announcement of the release. You can get it updated on your system through NuGet or via npm.