Private and protected members in classes Private and protected members in a class affect their compatibility. When an instance of a class is

Value-based elements Value based elements are simply looked up by identifiers that are in scope.

Hybrid Types As we mentioned earlier, interfaces can describe the rich types present in real world JavaScript. Because of JavaScript’s dynamic

Type Guards and Differentiating Types Union types are useful for modeling situations when values can overlap in the types they can take on.

Definition File Theory: A Deep Dive Structuring modules to give the exact API shape you want can be tricky. For example, we might want a module

Re-export to extend Often you will need to extend functionality on a module. A common JS pattern is to augment the original object with extensions

Functions with overloads When a function has overloads, each overload in the source type must be matched by a compatible signature on the target

Accessor Decorators An Accessor Decorator is declared just before an accessor declaration. The accessor decorator is applied to the

Symbol.isConcatSpreadable A Boolean value indicating that an object should be flatten to its array elements by Array.prototype

async/await support in ES6 targets (Node v4+) TypeScript now supports asynchronous functions for engines that have