@jest/types

What is @jest/types?

The @jest/types package provides TypeScript definitions and utility types for Jest, a popular JavaScript testing framework. It includes types for Jest configuration, global variables, and other utilities that help in creating type-safe test environments and extending Jest functionalities.

What are @jest/types's main functionalities?

Config

Defines types for Jest configuration options. This allows for type-safe Jest configuration files, ensuring that any configuration options passed to Jest are valid.

{"globals": {"myGlobal": "value"}, "testMatch": ["**/__tests__/**/*.js?(x)", "**/?(*.)+(spec|test).js?(x)"]}

Global

Provides types for Jest's global variables and functions, such as 'describe', 'it', and 'expect'. This is useful for creating custom global setups or mocks in a type-safe manner.

"declare var jest: jest.Jest"

Mock

Includes types for Jest's mocking utilities, enabling developers to create and manipulate mocks with full TypeScript support.

"const mockedFunction: jest.Mock = jest.fn()"

Other packages similar to @jest/types

@types/jest

Before Jest provided its own TypeScript definitions, @types/jest was the go-to package for Jest types. It serves a similar purpose by providing type definitions for Jest, but @jest/types is more up-to-date and maintained by the Jest team.

ts-jest

While ts-jest is primarily a TypeScript preprocessor for Jest, allowing Jest to understand TypeScript files, it also includes some utility types for configuration. However, @jest/types focuses solely on providing comprehensive type definitions for Jest's API.

jest-mock-extended

jest-mock-extended provides extended types and utilities for mocking in Jest, particularly with TypeScript. It complements @jest/types by offering more detailed mock creation and manipulation capabilities, though @jest/types provides the foundational type definitions.

README

The README file is missing

Changelog

27.5.1

Features

• [jest-config] Support comments in JSON config file (#12316)
• [pretty-format] Expose ConvertAnsi plugin (#12308)

Fixes

• [expect] Add type definitions for asymmetric closeTo matcher (#12304)
• [jest-cli] Load binary via exported API (#12315)
• [jest-config] Replace jsonlint with parse-json (#12316)
• [jest-repl] Make module importable (#12311 & #12315)

Chore & Maintenance

• [*] Avoid anonymous default exports (#12313)