Set prototype methods

Set.prototype.filter

Added to make all collections similar in capabilities. Should mimic Array.prototype.filter as close as reasonable.

Set.prototype.map

Added to make all collections similar in capabilities. Should mimic Array.prototype.map as close as reasonable.

Set.prototype.find

Added to make all collections similar in capabilities. Should mimic Array.prototype.find as close as reasonable.
Problematic behaviour

Set.prototype.reduce

Added to make all collections similar in capabilities. Should mimic Array.prototype.reduce as close as reasonable.
Static linters can check if function used by Set.prototype.reduce is associative and commutative. Otherwise, results can be surprising to user.

Set.prototype.join

Added to make all collections similar in capabilities. Should mimic Array.prototype.join as close as reasonable.

Set.prototype.some

Added to make all collections similar in capabilities. Should mimic Array.prototype.some as close as reasonable.

Set.prototype.every

Added to make all collections similar in capabilities. Should mimic Array.prototype.every as close as reasonable.

Set.prototype.addAll

Set.prototype.add can't be extended due to pattern of arr.forEach(set.add, set) and arr.forEach(set.add.bind(set)).
Doesn't create new set like Set.prototype.union

Set.prototype.deleteAll

Set.prototype.delete can't be extended due to pattern of arr.forEach(set.delete, set) and arr.forEach(set.delete.bind(set)).

Map prototype methods

Map.prototype.filter

Added to make all collections similar in capabilities. Should mimic Array.prototype.filter as close as reasonable.

Map.prototype.mapValues

TBA

Map.prototype.mapKeys

TBA

Map.prototype.reduce

Added to make all collections similar in capabilities. Should mimic Array.prototype.reduce as close as reasonable.

Map.prototype.find

Added to make all collections similar in capabilities. Should mimic Array.prototype.find.
This methods find value and returns it. It can be reasonable to return pair [key, value] or merge it with findKey.

Map.prototype.findKey

This methods find value and returns its key. It can be reasonable to return pair [key, value] or merge it with find.

Map.prototype.keyOf(searchElement)

This methods returns first key where SameValueZero(p.[[Value]], searchElement) is true.

Map.prototype.some

Added to make all collections similar in capabilities. Should mimic Array.prototype.some as close as reasonable.

Map.prototype.every

Added to make all collections similar in capabilities. Should mimic Array.prototype.some as close as reasonable.

Map.prototype.includes

Added to make all collections similar in capabilities. Should mimic Array.prototype.includes as close as reasonable.

Map.prototype.update

TBA

Map.prototype.deleteAll

TBA

Map.prototype.merge

TBA

Map static methods

Map.groupBy

TBA

Map.keyBy

TBA