prefer-jest-mocked.md

Pattern: Type assertion for mock

Issue: -

Description

Using type assertions with Jest's mock types (jest.Mock, jest.MockedFunction, etc.) is less type-safe than using the jest.mocked() helper function, which properly preserves type information.

Examples

Example of incorrect code:

(foo as jest.Mock).mockReturnValue(1);
const mock = (someFunction as jest.Mock).mockReturnValue(true);
(obj.method as unknown as jest.Mock).mockReturnValue("value");

Example of correct code:

jest.mocked(foo).mockReturnValue(1);
const mock = jest.mocked(someFunction).mockReturnValue(true);
jest.mocked(obj.method).mockReturnValue("value");