The has() method of Map instances returns a boolean indicating whether an element with the specified key exists in this map or not.

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

The delete() method of Set instances removes a specified value from this set, if it is in the set.

The byteLength accessor property of DataView instances returns the length (in bytes) of this view.

The getInt8() method of DataView instances reads 1 byte at the specified byte offset of this DataView and interprets it as an 8-bit signed 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 some() method of Iterator instances is similar to Array.prototype.some(): it tests whether at least one element produced by the iterator passes the test implemented by the provided function. It returns a boolean value.

The BigInt.asIntN() static method truncates a BigInt value to the given number of least significant bits and returns that value as a signed integer.

The BigInt.asUintN() static method truncates a BigInt value to the given number of least significant bits and returns that value as an unsigned integer.

The valueOf() method of BigInt values returns the wrapped primitive value of a BigInt object.