The Symbol.species static data property represents the well-known symbol @@species. Methods that create copies of an object may look up this symbol on the object for the constructor function to use when creating the copy.

The Symbol.isConcatSpreadable static data property represents the well-known symbol @@isConcatSpreadable. The Array.prototype.concat() method looks up this symbol on each object being concatenated to determine if it should be treated as an array-like object and flattened to its array elements.

The setInt16() method of DataView instances takes a number and stores it as a 16-bit signed integer in the 2 bytes starting at the specified byte offset of this DataView. There is no alignment constraint; multi-byte values may be stored at any offset within bounds.

The WeakSet() constructor creates WeakSet objects.

The resolvedOptions() method of Intl.DisplayNames instances returns a new object with properties reflecting the locale and style formatting options computed during the construction of this Intl.DisplayNames object.

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

The format() method of Intl.NumberFormat instances formats a number according to the locale and formatting options of this Intl.NumberFormat object.

The format() method of Intl.DurationFormat instances formats a duration according to the locale and formatting options of this Intl.DurationFormat object.

The resolvedOptions() method of Intl.PluralRules instances returns a new object with properties reflecting the locale and plural formatting options computed during initialization of this Intl.PluralRules object.

The formatRangeToParts() method of Intl.DateTimeFormat instances returns an array of locale-specific tokens representing each part of the formatted date range produced by this Intl.DateTimeFormat object.