Nodejs

The reactor pattern and libuv and the basic building blocks of Node.

promise.

Hooking into runtime-level object meta-operations.

destination object.

Cleaner data-structure for common algorithms based on sets.

Unique and immutable data type to be used as an identifier for object properties.

Support for exporting/importing values from/to modules without global namespace pollution.

Shorter syntax for common object property definition idiom.

Simple and intuitive default values for function parameters.

Support for constants (also known as "immutable variables"), i.