# What changed in jest-mock-extended

> 4 changes in jest-mock-extended 3 to 4 from its official release notes, upgrade guides and advisories: 1 breaking, 1 new APIs and options. Each one cited. Sources checked 2026-10-27. HTML: https://unstale.sh/npm/jest-mock-extended/

To see which of these apply to a repository, run `npx @unstale/cli init` in it.

## jest-mock-extended 4

### Breaking changes

- Object arguments are compared by value, so equivalent object literals match even when they are different references. (4.0.1) — [release notes](https://github.com/marchaos/jest-mock-extended/releases/tag/4.0.1)

### Tooling

- The TypeScript peer dependency range now includes ^6.0.0, allowing projects using TypeScript 6. (4.0.1) — [release notes](https://github.com/marchaos/jest-mock-extended/releases/tag/4.0.1)

### Fixes and other changes

- Mocked function properties regain inferred argument and return types, improving typing for overloaded methods on flat and deep mocks. (4.0.1) — [release notes](https://github.com/marchaos/jest-mock-extended/releases/tag/4.0.1)

## jest-mock-extended 3

### New APIs and options

- Deep mocking functions with properties requires setting funcPropSupport to true, which incurs a recursive performance cost. (3.0.0) — [release notes](https://github.com/marchaos/jest-mock-extended/releases/tag/3.0.0)