The Reflect.deleteProperty() static method is like the delete operator, but as a function. It deletes a property from an object.

The handler.has() method is a trap for the [[HasProperty]] object internal method, which is used by operations such as the in operator.

The take() method of Iterator instances returns a new iterator helper that yields the given number of elements in this iterator and then terminates.

The every() method of Iterator instances is similar to Array.prototype.every(): it tests whether all elements produced by the iterator pass the test implemented by the provided function. It returns a boolean value.

The Iterator() constructor is intended to be used as the superclass of other classes that create iterators. It throws an error when constructed by itself.

The Math.expm1() static method returns e raised to the power of a number, subtracted by 1. That is

The Intl.supportedValuesOf() static method returns an array containing the supported calendar, collation, currency, numbering systems, or unit values supported by the implementation.

The [@@iterator]() method of Iterator instances implements the iterable protocol and allows built-in iterators to be consumed by most syntaxes expecting iterables, such as the spread syntax and for...of loops. It returns the value of this, which is the iterator object itself.

The drop() method of Iterator instances returns a new iterator helper that skips the given number of elements at the start of this iterator.

The Symbol.keyFor() static method retrieves a shared symbol key from the global symbol registry for the given symbol.