ClojureやHaskellのような不変データ構造体のJS実装です。facebook製。 不変データ構造の特徴として、元のデータ構造は不変です。 Immutable = require 'immutable' map1 = Immutable.Map a: 1, b: 2 # => Map {a: 1, b: 2} map2 = map1.set a: 3 #=> Map {a: 3, b: 2} map3 = map1.update (val) -> {foo: val.a} #=> Map {foo: 1} Mapの他に、List, OrderedMap, Set, OrederedSet, Seq, Range, Record, Stack等があります。内部的にはトライ木になっています。 面白いのはSeqやRangeで、filter関数やmap関数を与えても、getで呼ばれるまで遅
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