The union() method of Set instances takes a set and returns a new set containing elements which are in either or both of this set and the given set.

The size accessor property of Set instances returns the number of (unique) elements in this set.

The clear() method of Map instances removes all elements from this map.

The entries() method of Set instances returns a new set iterator object that contains an array of [value, value] for each element in this set, in insertion order. For Set objects there is no key like in Map objects. However, to keep the API similar to the Map object, each entry has the same value for its key and value here, so that an array [value, value] is returned.

The Object.defineProperties() static method defines new or modifies existing properties directly on an object, returning the object.

The setDate() method of Date instances changes the day of the month for this date according to local time.

The GeneratorFunction() constructor creates GeneratorFunction objects.

The italics() method of String values creates a string that embeds this string in an <i> element (<i>str</i>), which causes this string to be displayed as italic.

The Function() constructor creates Function objects. Calling the constructor directly can create functions dynamically, but suffers from security and similar (but far less significant) performance issues as eval(). However, unlike eval (which may have access to the local scope), the Function constructor creates functions which execute in the global scope only.

The forEach() method of Map instances executes a provided function once per each key/value pair in this map, in insertion order.