Jest Environment JSDOM saw a notable update moving from version 25.5.0 to 26.0.0, impacting the testing landscape for JavaScript developers leveraging Jest with JSDOM. The update primarily involves dependency upgrades. JSDOM, the core DOM implementation for testing, jumps from version 15.2.1 to 16.2.2, potentially introducing new features and bug fixes related to DOM manipulation and browser environment simulation. Jest's internally managed packages like jest-mock, jest-util, @jest/types, @jest/environment, and @jest/fake-timers are all updated to version 26.0.0, ensuring internal consistency and access to the latest testing utilities from Jest like mocks and types.
Furthermore, the @types/jsdom declaration files for TypeScript users are enhanced, moving from version 12.2.4 to 16.2.1, providing more accurate and comprehensive type definitions for JSDOM's API. This upgrade provides better type checking and autocompletion in TypeScript projects, improving the developer experience. While the core functionality of jest-environment-jsdom might not be radically different, developers should be aware of potential breaking changes introduced by the newer JSDOM version and Jest internal packages which may change behaviour of tests subtly or even require test updates. The updated type definitions represent a substantial quality-of-life improvement for TypeScript users. The release date diff of the two versions is about one week, meaning there was fast iteration and that the update might not be particularly groundbreaking.
The are not vulnerabilities for the version 26.0.0 of the package jest-environment-jsdom
