The lastIndexOf() method of TypedArray instances returns the last index at which a given element can be found in the typed array, or -1 if it is not present. The typed array is searched backwards, starting at fromIndex. This method has the same algorithm as Array.prototype.lastIndexOf().

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 Intl.DurationFormat object enables language-sensitive duration formatting.

The Intl.Collator object enables language-sensitive string comparison.

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

The Math.round() static method returns the value of a number rounded to the nearest integer.

The slice() method of ArrayBuffer instances returns a new ArrayBuffer whose contents are a copy of this ArrayBuffer's bytes from start, inclusive, up to end, exclusive. If either start or end is negative, it refers to an index from the end of the array, as opposed to from the beginning.

The Math.sinh() static method returns the hyperbolic sine of a number. That is,

The Math.asinh() static method returns the inverse hyperbolic sine of a number. That is,

The Number.NaN static data property represents Not-A-Number, which is equivalent to NaN. For more information about the behaviors of NaN, see the description for the global property.