xset

Subclass of JavaScript's built-in Set with extra methods.

Usage:

Install:

install --save @gjmcn/xset

The module has a single named export: XSet.

Methods

Use any Set methods as well as:

Method	Description	Return
copy()	Shallow copy. xs.copy() is equivalent to new XSet(xs).	xset
adds(iterable)	Add each element of iterable to the xset.	xset
deletes(iterable)	Delete each element of iterable from the xset.	xset
filter(f, returnArray)	Each element is passed to the function f; if f returns a truthy value, the element is included in the result. If returnArray is truthy, filter returns a new array, otherwise returns a new xset.	xset or array
map(f, returnArray)	Each element is passed to the function f; the returned values are collected in a new array (if returnArray is truthy) or a new xset.	xset or array
count(f)	Each element is passed to the function f; count returns the number of times that f returns a truthy value.	number
find(f)	Each element is passed to the function f; the first time f returns a truthy value, the corresponding element is returned. find returns undefined if no element produces a truthy value.	any
every(f)	Each element is passed to the function f; if f returns a truthy value every time, every returns true — and returns false otherwise.	boolean
some(f)	Each element is passed to the function f; the first time f returns a truthy value, some returns true. If f returns a falsy value every time, some returns false.	boolean
first()	First element of the set, or undefined if the set is empty.	any
difference(iterable1, iterable2, ...)	Returns a new xset containing every element in the calling xset that is not in any of the passed iterables.	xset
intersection(iterable1, iterable2, ...)	Returns a new xset containing every element that appears in the calling xset and all of the passed iterables. The order of elements in the returned xset matches their order in the calling xset.	xset
union(iterable1, iterable2, ...)	Returns a new xset containing every element that appears in the calling xset or any of the passed iterables. The order of elements in the returned xset is based on their first occurrence in the calling xset and iterables.	xset

Example

const s = new XSet([3, 4, 5]);   // XSet {3, 4, 5}
s.add(10);                       // XSet {3, 4, 5, 10}
s.adds([20, 30]);                // XSet {3, 4, 5, 10, 20, 30}

s.filter(e => e < 15);           // new Xset {3, 4, 5, 10}
s.intersection([0, 5, 10, 15]);  // new XSet {5, 10}