get Set[@@species]

The Set[Symbol.species] accessor property returns the Set constructor.

The species accessor property returns the default constructor for Set objects. Subclass constructors may override it to change the constructor assignment.

The species property returns the default constructor function, which is the Set constructor for Set objects:

Set[Symbol.species]; // function Set()

In a derived collection object (e.g. your custom set MySet), the MySet species is the MySet constructor. However, you might want to overwrite this, in order to return parent Set objects in your derived class methods:

class MySet extends Set {
  // Overwrite MySet species to the parent Set constructor
  static get [Symbol.species]() { return Set; }
}

• Set
• Symbol.species