The following libraries allow us to take advantage of immutability in TypeScript:
| Library | Description | Link |
| monocle-ts | Functional optics: A (partial) porting of Scala monocle to TypeScript. | https://github.com/gcanti/monocle-ts |
| lens.ts | A TypeScript Lens implementation with property proxy. | https://github.com/utatti/lens.ts |
| Lenses | A small functional lens library for TypeScript with the goal of being small, with zero dependencies, and strong, precise types. It is inspired by Aether, for F#. | https://github.com/atomicobject/lenses |
| Lenticular.ts | An implementation of functional lenses in JavaScript/TypeScript. | https://github.com/tomasdeml/lenticular.ts |