Overview

Miso.Data.Set is a Haskell wrapper around the JavaScript Set object. Values of type Set a live in JavaScript memory; all operations run in IO and mutate the underlying JS set in place.

Unlike Set, elements do not require an Ord instance — any type with a ToJSVal instance can be stored, and equality is determined by JavaScript's SameValueZero algorithm.

Use this module when you need to share a set with a browser API or a third-party JavaScript library. For pure Haskell processing, prefer Set.

Import qualified to avoid clashing with Prelude:

import qualified Miso.Data.Set as S

Quick start

import qualified Miso.Data.Set as S

example :: IO ()
example = do
  s  <- S.fromList [1, 2, 3 :: Int]
  S.insert 4 s
  b  <- S.member 2 s   -- True
  n  <- S.size s       -- 4
  S.delete 1 s
  pure ()

Operations

• Construction: new, fromList
• Access: member, size
• Mutation: insert, delete, clear
• Set algebra: union, intersection, difference, isSubset, isSuperset, isDisjoint

See also

• Miso.Data.Array — mutable JS Array
• Miso.Data.Map — mutable JS Map
• Miso.DSL — ToJSVal / FromJSVal used by element types