Upgrading to Jasmine 5.0


Most users will be able to upgrade to Jasmine 5.0 without making any changes. However, it does contain a few breaking changes that will affect some users. Following the advice in this guide will give you the greatest chance of a smooth upgrade experience.

Breaking changes in Jasmine 5.0 include changes to how backslashes are handled in file globs on Windows, changes to how Env#execute is called, changes to how Node-based libraries boot jasmine-core, and changes to the system requirements. You can find a complete list of breaking changes in the release notes for jasmine-core and jasmine .

All users are encouraged to upgrade to the latest 4.x release and resolve any errors or deprecation warnings prior to upgrading to 5.0. In particular, people who use the jasmine package on Windows should upgrade to at least 4.5.0 first because that release adds an important deprecation warning that affects Windows users. For the same reason, people who use the jasmine-browser-runner package on Windows should upgrade that package to at least 1.3.0 prior to upgrading it to 2.0.

The new parallel execution mode introduced in Jasmine 5.0 comes with additional restrictions on how both specs and reporters are written. These restrictions apply only when Jasmine is run in the parallel mode. See the guide to parallel execution for details.


  1. System requirements
  2. Upgrading jasmine-browser-runner
  3. Changes to backslash handling on Windows
  4. Support for parallel execution
  5. Changes to global error handling in browsers
  6. Changes to Env#execute
  7. node_boot.js removal

System requirements

The following previously-supported environments are no longer supported:

Although Jasmine 5.0 may still work in some of those environments, we no longer test against them and won’t try to maintain compatibility with them in future 5.x releases.

Upgrading jasmine-browser-runner

If you’re using jasmine-browser-runner, upgrade to version 2.0. Your package manager (npm/yarn/etc) should automatically install jasmine-core 5.0 or later unless your package.json specifies an earlier version.

Changes to backslash handling on Windows

Historically, backslashes in file globs such as the spec_files configuration property were treated as directory separators on Windows and as the start of an escape sequence on other operating systems. Beginning with jasmine 5.0 and jasmine-browser-runner 2.0, they are treated as the start of an escape sequence on all operating systems. This change makes Jasmine configuration files more portable and ensures that Windows users can specify filenames that happen to match special glob syntax. See the glob package’s changelog and README for more information.

Deprecation warnings related to backslashes were added in jasmine 4.6.0 and jasmine-browser-runner 1.3.0. Windows users should upgrade to those versions or later and resolve all deprecation warnings before upgrading to jasmine 5.x or jasmine-browser-runner 2.x.

Support for parallel execution

The biggest change in 5.0 is support for parallel execution in Node.js via the jasmine package. Parallel execution imposes some constraints on both test suites and reporters, and as a result not everyone will be able to adopt it without making changes. See Running Specs in Parallel for more information.

Changes to global error handling in browsers

Previous versions of Jasmine detected unhandled exceptions and unhandled promise rejections in browsers by installing a window.onerror handler. 5.0 and later use addEventListener instead. This means that Jasmine will no longer override any error handler that your code installs prior to startup. It also means that you can no longer override Jasmine’s global error handling by setting window.onerror. If you need to override Jasmine’s global error handling, use spyOnGlobalErrors.

Using addEventListener allows Jasmine to provide better error information in many cases. However, some browsers limit the information that’s provided to error listeners when the source of the error was loaded from a file:// URL. If you’re using the standalone distribution, you may find it easier to debug unhandled exceptions and promise rejections if you load Jasmine via a web server. An easy way to do this is to run npx serve from the directory containing SpecRunner.html.

Changes to Env#execute

Jasmine 5.0 completes the migration of Env#execute to async/await. Most users don’t need to care about this because they either don’t call Env#execute directly or use it in a “fire and forget” fashion. However, anyone who’s either passing a callback to Env#execute or catching exceptions from it may need to make changes.


try {
    env.execute(null, function () {
        // Handle completion
} catch (e) {
    // Handle failures to start


try {
    const jasmineDoneInfo = await env.execute();
} catch (e) {
    // Handle failures to start, which are now delivered via promise rejection
    // rather than synchronous throw

Note to library authors

The “after” form works with jasmine-core 4.0.0 and later, or 3.9.0 and later if you ignore the value that the promise is resolved to.

node_boot.js removal

This change mainly affects authors of libraries that wrap jasmine-core in Node.js, not end users. Prior to 5.0, the boot function used to initialize jasmine-core in Node was provided via jasmine-core/node_boot.js and also exported on the jasmine-core module itself. node_boot.js no longer exists in 5.0.


const boot = require('jasmine-core/node_boot.js');


const boot = require('jasmine-core').boot;

The “After” version should work in all versions of jasmine-core that support Node.js.