# Mutative: immutable updates without the spread syntax

Canonical source : [Mutative: immutable updates without the spread syntax](<https://sebastien.rigaux.be/en/tech-watch/links/mutative-immutable-updates-without-the-spread-syntax>)

Mutative lets developers write mutations against a draft to produce a new immutable state, avoiding manual spread copies at every level. It also supports arrays, `Set` and `Map`, along with patches and optional freezing.

Its benchmarks report a geometric mean 3.6 times faster than Immer with matched settings, or 6.6 times with each library’s defaults. Results vary by workload; hand-written reducers remain faster in most of the cases shown.

- Selected on : 2026-10-23

- Entry updated : 2026-11-07T20:32:37+0000

- Format : Article

- Source language : EN

Original resource : [Mutative: immutable updates without the spread syntax](<https://mutative.js.org/>)

Tags : [JavaScript](<https://sebastien.rigaux.be/en/tech-watch/tags/javascript>) · [State management](<https://sebastien.rigaux.be/en/tech-watch/tags/state-management>)

Available versions : [Français](<https://sebastien.rigaux.be/veille/liens/mutative-des-mises-a-jour-immuables-sans-spread>) · [English](<https://sebastien.rigaux.be/en/tech-watch/links/mutative-immutable-updates-without-the-spread-syntax>)

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