npm / immer

immer

What changed in immer 10 to 11, from its official release notes, upgrade guides and advisories. Sources checked 2026-10-17.

2 breaking1 security3 new APIs and options2 performance18 fixes and other

See which of these apply to your code, ranked, in your agent:

npx @unstale/cli init

@unstale/cli 0.1.1 on npm

immer 1124 changes

Breaking changes 2

Reads of a revoked Map or Set draft now throw.
11.1.21release notes
Loose iteration is enabled by default.
11.0.0release notes

Security 1

Prevents prototype pollution via constructor.prototype access.
11.1.9release notes

New APIs and options 2

Adds an optional plugin that overrides specified draft array methods to operate directly on the underlying array, significantly speeding up array operations.
11.1.0release notes
With the plugin enabled, array items passed to callbacks are not automatically wrapped in Proxies, so mutating them can change the underlying objects.
11.1.0release notes

Performance 1

Finalization now uses targeted callbacks instead of recursive tree traversal, improving performance.
11.0.0release notes

Fixes and other changes 18

A deletion is no longer recorded when a base value is written back.
11.1.20release notes
The array-methods plugin now forwards thisArg, so callbacks receive the intended this value.
11.1.19release notes
Removed the global var declaration for Iterator that conflicted with the ESNext lib.
11.1.18release notes
Preserves structural sharing for no-op array-method calls.
11.1.17release notes
Inserted array indices are keyed by name in the array-methods plugin.
11.1.16release notes
Corrected the return type of curried produceWithPatches.
11.1.15release notes
Throws the proper Immer error when an applyPatches path traverses null.
11.1.14release notes
Fixes relocated base references for drafts after reverse or sort in the array-methods plugin.
11.1.13release notes
Reverts the prevention of prototype pollution via constructor.prototype access.
11.1.12release notes
Improves DraftMap.entries() compatibility.
11.1.11release notes
Improves DraftMap.values() compatibility.
11.1.11release notes
Assigning undefined to a prototype-inherited key no longer gets dropped.
11.1.10release notes
The typings now assert that the draft value is unwrapped.
11.1.8release notes
The typings now assert that the draft value is unwrapped.
11.1.8release notes
Higher-order type inference for WritableDraft is improved.
11.1.7release notes
Removes an invalid curried producer type.
11.1.6release notes
Handles nested proxies after spreading and inserting into an array.
11.1.4release notes release notes
Fixes recursive T for WritableDraft.
11.1.3release notes

immer

immer 1124 changes

Breaking changes 2

Security 1

New APIs and options 2

Performance 1

Fixes and other changes 18

immer 102 changes

New APIs and options 1

Performance 1