The readme explains in more detail: https://github.com/unadlib/mutative#readme https://github.com/unadlib/mutative#readme > Immer must have auto-freeze enabled

The readme explains in more detail: https://github.com/unadlib/mutative#readme https://github.com/unadlib/mutative#readme > Immer must have auto-freeze enabled by default(Performance will be worse if auto-freeze is disabled), such immutable state with Immer is not common. In scenarios such as cross-processing, remote data transfer, etc., we have to constantly freeze these immutable data. > There are more parts that could be improved, such as better type inference, non-intrusive markup, support for more types of immutability, Safer immutability, more edge cases, and so on. Also compared to native spread operation(naive handcrafted reducer): > The spread operation has performance pitfalls... > And Mutative optimization focus on shallow copy optimization, more complete lazy drafts, finalization process optimization, and more.