TypeScript 2.1

• keyof and Lookup Types
• Mapped Types
• Partial, Readonly, Record, and Pick
• Object Spread and Rest
• Downlevel Async Functions
• Support for external helpers library (tslib)
• Untyped imports
• Support for –target ES2016, –target ES2017 and –target ESNext
• Improved any Inference
• Implicit any errors
• Better inference for literal types
• Use returned values from super calls as ‘this’
• Configuration inheritance
• New –alwaysStrict