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jest-watcher
Advanced tools
Package description
The jest-watcher package is a part of the Jest ecosystem and is used to implement custom watch plugins for Jest. It provides an API to create plugins that can hook into Jest's watch mode, allowing developers to add custom watch behaviors to their test suites.
Custom Watch Plugins
This feature allows developers to create custom watch plugins that can react to file changes, determine if a test suite should run, and more. The code sample shows a basic structure of a custom watch plugin.
class MyCustomPlugin {
apply(jestHooks) {
jestHooks.onFileChange(({ projects }) => {
console.log('Files changed:', projects[0].changedFiles);
});
jestHooks.shouldRunTestSuite(() => true);
}
}
module.exports = MyCustomPlugin;
Interactive Watch Plugins
This feature allows the creation of interactive watch plugins that can provide custom interactive CLI interfaces during Jest's watch mode. The code sample demonstrates how to implement an interactive behavior that filters tests based on a pattern.
class MyInteractivePlugin {
run(globalConfig, updateConfigAndRun) {
// Implement interactive behavior here
updateConfigAndRun({
testNamePattern: 'pattern to filter tests'
});
return Promise.resolve();
}
}
module.exports = MyInteractivePlugin;
Mocha-watch is a watch mode for Mocha testing framework. It provides similar functionality to jest-watcher by re-running tests when file changes are detected. However, it is tailored for Mocha and does not offer the same plugin API for extending watch behavior.
Karma is a test runner that works with multiple testing frameworks like Jasmine, Mocha, and QUnit. It can watch files and re-run tests on changes, similar to jest-watcher. Karma is more of a full-fledged test runner with a focus on running tests in different browsers, whereas jest-watcher is specifically for creating watch plugins in Jest.
AVA is a test runner with built-in watch mode functionality. It automatically re-runs tests when it detects changes. AVA's watch mode is not plugin-based like jest-watcher, but it offers a simple and fast out-of-the-box solution for watching tests without the need for additional configuration.
Changelog
29.4.3
[expect]
Update toThrow()
to be able to use error cause
s (#13606)[jest-core]
allow to use workerIdleMemoryLimit
with only 1 worker or runInBand
option (#13846)[jest-message-util]
Add support for error cause
s (#13868 & #13912)[jest-runtime]
Revert import assertions
for JSON modules as it's been relegated to Stage 2 (#13911)[@jest/expect-utils]
subsetEquality
should consider also an object's inherited string keys (#13824)[jest-mock]
Clear mock state when jest.restoreAllMocks()
is called (#13867)[jest-mock]
Prevent mockImplementationOnce
and mockReturnValueOnce
bleeding into withImplementation
(#13888)[jest-mock]
Do not restore mocks when jest.resetAllMocks()
is called (#13866)FAQs
Delightful JavaScript Testing.
We found that jest-watcher demonstrated a healthy version release cadence and project activity because the last version was released less than a year ago. It has 5 open source maintainers collaborating on the project.
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