npm msw 2.0.0
v2.0.0

latest releases: 2.6.4, 2.6.3, 2.6.2...
12 months ago

v2.0.0 (2023-10-23)

Important

This release is a BREAKING CHANGE. Please follow the Migration guidelines to upgrade. This release took a lot of effort to make, and I expect a bit of that effort on your part while upgrading. Most of the changes are mechanical, and a simple Find/Replace All will get you a long way. For the rest of it, you will learn how to handle requests and responses using the standard JavaScript API. Thank you!

Breaking changes

  • Drops support for Node.js 16. Please upgrade to Node.js 18 or later to use the global Fetch API.
  • Drops support for TypeScript < 4.7.
  • All browser-side exports, like setupWorker, SetupWorkerApi, etc., must be imported from msw/browser now.
  • Renames the rest object to http (rest.get -> http.get).
  • Response resolver call signature is no longer (req, res, ctx) => res() but instead ({ request }) => new Response().
  • The following exports are removed due to no longer being needed:
    • response
    • context and related exports (defaultContext, restContext, graphqlContext).
    • compose and createResponseComposition
  • res.once() is removed in favor of the { once: boolean } option on the request handler.
  • Replaces the .printHandlers() method with .listHandlers().
  • Removes the NetworkError class in favor of the standard Response.error().
  • Moves request error handling from the worker thread to the client thread.
  • Changes the call signature of the Life-cycle Events API to accept a single object argument.
  • Uses crypto.randomUUID() instead of Math.random() in the worker.
  • For the full list of changes and detailed instructions on how to upgrade please see the Migration guidelines.

Features

  • Adopts Fetch API primitives. Represent intercepted requests and mocked responses as Request and Response instances respectively.
  • Supports Node.js v18.
  • Supports ReadableStream as a mocked response body.
  • Supports reading the intercepted request body as FormData.
  • Supports FormData as a mocked response body.
  • Uses File polyfill in Node.js.
  • Supports XMLHttpRequest “upload” events when responding with a mocked stream response.
  • Allows mocking a network error once using the { once: true } request handler option.
  • Makes the RequestHandler API public.

Bug fixes

  • Fixes the issue where the request body couldn’t be properly read as FormData.
  • Fixes a set of issues related to response patching when using the FormData response body.
  • Fixes the issue where URLSearchParams as the request body couldn’t be read.
  • Fixes the issue where a bypassed request’s referrerPolicy was reset to a different value than the original.
  • Fixes the wrong order of XMLHttpRequest events and readyState changes.
  • Fixes the issue when reading an XMLHttpRequest body of responseType equal to "arraybuffer" as an incorrect buffer (previously, always assumed to be a string).
  • Fixes the order of XMLHttpRequest events when the request fails.
  • Keeps XMLHttpRequest status equal to 0 until the request actually resolves.
  • Fixes the issue when the onload event callback was called twice for XMLHttpRequest.
  • Various improvements in Node.js network behavior compliance.

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