The builders of CoffeeScript laud the inclusion of features such as destructuring and classes in ECMAScript. “We are happy that ECMA has seen their utility and adopted them into ECMAScript,” they said.
CoffeeScript compiles its "class" and "extends" keywords to ES2015 classes. In addition, ES2015 modules are supported. However, there are also features—such as let and const, for declaring variables within a block scope—that CoffeeScript intentionally does not support for simplicity’s sake.
CoffeeScript has previously cracked the top 100 of the monthly Tiobe Index of language popularity, although it did not make it onto that list in this month’s tally.