Support number and symbol named properties with keyof and mapped types Example Example Recommendations Generic type arguments in JSX elements Example Generic type argument...
Project References Tuples in rest parameters and spread expressions Rest parameters with tuple types Spread expressions with tuple types Generic rest parameters Example Optio...
Smarter Type Alias Preservation Leading/Middle Rest Elements in Tuple Types Stricter Checks For The in Operator --noPropertyAccessFromIndexSignature abstract Construct Signa...
About this Handbook How is this Handbook Structured Non-Goals Get Started About this Handbook Over 20 years after its introduction to the programming community, JavaScript i...
Using TypeScript --no-check option Using external type definitions Compiler hint Triple-slash reference directive in JavaScript files X-TypeScript-Types custom header Custom ...
Using TypeScript --no-check option Using external type definitions Compiler hint Triple-slash reference directive in JavaScript files X-TypeScript-Types custom header Custom ...
Performance Improvements Better Module Visibility Rules Performance Improvements The 1.1 compiler is typically around 4x faster than any previous release. See this blog post f...
Null- and undefined-aware types —strictNullChecks Example Assigned-before-use checking Example Optional parameters and properties Non-null and non-undefined type guards Examp...
keyof and Lookup Types Example Example Mapped Types Partial, Readonly, Record, and Pick Object Spread and Rest Downlevel Async Functions Example tsconfig.json dramaticWelco...