structural-sharing

A very fast and lightweight Typescript library to create immutable states with a mutable syntax

No-Frills Functional Programming Lib Augmenting Javascript/Node.js

Statically-typed structural-sharing tree modifier

Use plain JS types as immutable data, with efficient merging and memory sharing

Returns native JavaScript types (Array/Object/Map/Set). Immutability faster than mutation. Dual mode: immutable + mutable patterns. 100% library compatible.

JSON Merge Patch that understands keyed lists

immutable nested-state updates via a command-spec DSL

Immutable composition IR with exact-base commit diffs, shared by document frontends

Typed, serialisable tree structures for TypeScript: build forests from flat rows (strict or tolerant), traverse with cursors, edit copy-on-write with structural sharing, flatten back to rows. Zero dependencies, JSON-safe nodes. Consumed in production by Topos and adaptive-learner.

Typesafe dot-path middleware for Zustand — deep get, set, subscribe, and reset with a single string path. Cached parsing, structural sharing, zero closures.

Immutable nested update with structural sharing

High-performance deep merge utility with structural sharing. Supports circular ref and complex built-in types.