TypeScript 3.0 TypeScript 3.0 Tuples in rest parameters and spread expressions New unknown top type Support for defaultProps in JSX reference directives

TypeScript 1.3 Protected Tuple types TypeScript 1.3 Protected The new protected modifier in classes works like it does in familiar languages like C++, C#, and Java. A prot...

TypeScript 1.5 ES6 Modules Export Declarations Re-exporting Default Export Bare Import Destructuring in declarations and assignments Declarations Assignments namespace key...

TypeScript 2.0 Null- and undefined-aware types —strictNullChecks Example Assigned-before-use checking Example Optional parameters and properties Non-null and non-undefined t...

TypeScript 2.1 keyof and Lookup Types Example Example Mapped Types Partial, Readonly, Record, and Pick Object Spread and Rest Downlevel Async Functions Example tsconfig.jso...

TypeScript 2.2 Support for Mix-in classes First some terminology Putting all of the above rules together in an example object type Support for new.target Example Better chec...

TypeScript 3.5 Speed improvements Type-checking speed-ups —incremental improvements The Omit helper type Improved excess property checks in union types The —allowUmdGlobalAcce...

Generators and Iteration for ES5/ES3 Iterators Generators New —downlevelIteration Async Iteration Async iterators Async Generators The for-await-of Statement Caveats Gener...

Optional catch clause variables Type assertion/cast syntax in checkJs/@ts-check mode Deduplicated and redirected packages The —preserveSymlinks compiler flag Optional catch ...

Support number and symbol named properties with keyof and mapped types Example Example Recommendations Generic type arguments in JSX elements Example Generic type arguments i...