immutable

Uses hash map tries and vector tries to minimize memory overhead and copying, enabling persistent data structures that yield new data on mutation without full duplication, as highlighted in the introduction.

Provides .equals() and Immutable.is() for treating collections as values, allowing them to be used as keys in Maps or Sets, which is emphasized in the 'Equality treats Collections as Values' section.

Mirrors ES2015 Array, Map, and Set APIs for seamless interoperability, with examples in the README showing how to convert from raw JavaScript objects and arrays.

Seq allows efficient chaining of operations like map and filter without creating intermediate collections, demonstrated with examples such as oddSquares in the 'Lazy Seq' section.

withMutations enables performant local updates by creating temporary mutable copies, reducing overhead when applying multiple mutations, as shown in the batching examples.