The get() method of Map instances returns the value corresponding to the key in this Map, or undefined if there is none. Object values are returned as the same reference that was originally stored, not as a copy, so mutations to the returned object will be reflected anywhere that reference is held, including inside the Map.

The toString() method of Array instances returns a string representing the specified array and its elements.

The left shift assignment operator `<<=`.

The handler.deleteProperty() method is a trap for the [[Delete]] object internal method, which is used by operations such as the delete operator.

An iterator over the command arguments.

The handler.isExtensible() method is a trap for the [[IsExtensible]] object internal method, which is used by operations such as Object.isExtensible().

The Intl.DurationFormat() constructor creates Intl.DurationFormat objects.

The Intl.NumberFormat() constructor creates Intl.NumberFormat objects.

An iterator over the `char`s of a string slice, and their positions.

The Object.isExtensible() static method determines if an object is extensible (whether it can have new properties added to it).