Head-to-Head: Polly.JS vs MSW Analysis

@pollyjs/core

v6.0.6(11 months ago)

This package is actively maintained.Types definitions are bundled with the npm packageNumber of direct dependencies: 9Monthly npm downloads

@pollyjs/core is a powerful and flexible JavaScript library for recording, replaying, and stubbing HTTP interactions in tests. It allows developers to create reliable and deterministic tests by capturing and replaying network requests and responses. With support for various adapters and plugins, Polly.js can be easily integrated into different testing frameworks and environments.

Alternatives:
nock+
axios-mock-adapter+
miragejs+
msw+
fetch-mock+
pretender+
sinon+
intercept-stdout+
jest-mock+
testdouble+

Tags: javascripttestinghttpmockingnetwork

msw

v2.3.1(21 days ago)

This package is actively maintained.Types definitions are bundled with the npm packageNumber of direct dependencies: 17Monthly npm downloads

MSW (Mock Service Worker) is a powerful library for mocking HTTP requests in development and testing environments. It allows developers to intercept network requests made by the application and provide mock responses, enabling isolated and predictable testing scenarios. MSW supports various request matching strategies, response customization options, and integration with popular testing frameworks like Jest and Cypress.

Alternatives:
nock+
miragejs+
axios-mock-adapter+
pretender+
json-server+
intercept-stdout+
fetch-mock+
betwixt+
stubby+
pollyjs+

Tags: javascriptmockingtestinghttpdevelopment

Fight!

Popularity

Both @pollyjs/core and msw are popular npm packages within the JavaScript community. Although @pollyjs/core has been around for longer, msw has gained significant attention and popularity in recent years.

Mocking and Stubbing

@pollyjs/core is primarily focused on advanced network request handling and offers powerful features for recording, replaying, and persisting HTTP interactions. It integrates seamlessly with different testing frameworks and allows you to stub responses and test network-dependent code effectively. On the other hand, msw is a modern and efficient mock service worker library that allows you to intercept and mock network requests made by the client application. It provides an intuitive API for handling requests, and its integration with testing frameworks is also straightforward.

Testing Ecosystem Integration

Both packages have excellent integrations with popular testing frameworks such as Jest, Mocha, and Cypress. @pollyjs/core, being more established, has a wide range of plugins and extensions that enhance its compatibility with multiple testing frameworks. Similarly, msw also has solid integration support and is frequently used in combination with testing frameworks for frontend and API testing.

Developer Experience

In terms of developer experience, both packages provide a smooth and intuitive API. However, @pollyjs/core is more feature-rich and offers additional capabilities such as request and response filtering, middleware support, and event hooks. msw, on the other hand, focuses on simplicity and ease of use, providing a clear and concise API for handling network requests.

Supported Environments

@pollyjs/core is primarily aimed at testing client-side JavaScript and supports various environments, including browser-based testing frameworks like Cypress and testing in Node.js environments. msw is built specifically for mocking network requests in client-side applications using modern JavaScript frameworks like React, Angular, and Vue.js.

Documentation and Community Support

Both packages have well-documented APIs and provide comprehensive guides that help users get started quickly. @pollyjs/core has been around for longer, so it has a stronger community presence with more active contributors. msw, although relatively newer, has a growing community and responsive maintainers.