jest-config
MOXY's Jest configuration to be used across several JavaScript projects.
Installation
$ npm install --save-dev jest @moxy/jest-config
How it works
This package contains a base configuration and a set of enhancers. You may combine them to configure Jest for different types of projects.
Base config
baseConfig
is the base point of this configuration. It includes all defaults offered by jest-config
, and has project agnostic configurations, meant to help any project regardless of their purpose, including:
-
Test match: Tweaks
testMatch
so that only files namedtest.js
or files ending with.test.js
are considered test files, even if they are inside__tests__
or any other folder. -
Test path ignore patterns: Tweaks
testPathIgnorePatterns
to ignore common folders, such asdocusaurus
. -
Transform: Enables Babel so that
jest.mock()
and similar functions are automatically hoisted to the top. If your project uses Babel, its config will be read and used to transpile code. -
Coverage: Enables coverage for CI, a feature supported by
ci-info
, which you can check for information about supported CI services. - Coverage thresholds: For a good balance between strict but workable thresholds.
- Snapshot serializing: To remove absolute paths from your snapshots, reducing conflicts in CI.
Enhancers
There are several enhancer packages, which are intended to be used in conjunction with the base configuration:
-
withWeb
- Adds setup for Web projects. -
withReactNative
- Adds setup for React Native projects. -
withRTL
- Adds setup for projects using Testing Library. -
withEnzymeWeb
&withEnzymeReactNative
- Adds setup for projects using Enzyme.
Usage
Create jest.config.js
at the root of your project:
const { baseConfig } = require('@moxy/jest-config');
module.exports = baseConfig();
The baseConfig
function accepts a optional parameter that allows to specify the Jest environment, which can be jsdom
(default) or node
. As an example, for Node.js projects you would use like so:
const { baseConfig } = require('@moxy/jest-config');
module.exports = baseConfig('node');
Alternatively, you may pass a path to a custom environment. In fact, we offer the following custom environments:
@moxy/jest-config/environments/node-single-context
Special Node environment class for Jest which runs all scripts in the same context. This effectively disables the sandbox isolation to circumvent issues with Jest's sandboxing, which causes subtle bugs in specific situations, such as in code that relies in instanceof
checks.
const { baseConfig } = require('@moxy/jest-config');
module.exports = baseConfig('@moxy/jest-config/environments/node-single-context');
⚠️ Only activate this environment if you are having problems with the aforementioned issue, and before trying other workarounds.
Composing enhancers
To use enhancers, use the compose
function that comes with this package. Keep in mind, the first item should always be the base configuration! Here's an example of using compose
:
const { compose, baseConfig, withWeb, withRTL } = require('@moxy/jest-config');
module.exports = compose(
baseConfig(),
withWeb(),
withRTL(),
);
You may also use compose
to add your own inline enhancer:
const { compose, baseConfig } = require('@moxy/jest-config');
module.exports = compose(
baseConfig(),
(config) => ({
...config,
// Do not test `.data.js` files
testPathIgnorePatterns: [
...config.pathIgnorePatterns,
'/.*.data.js$/'
];
}),
);
Without compose
If you want to modify the base config without using compose
, you may change the config imperatively like so:
const { baseConfig } = require('@moxy/jest-config');
const config = baseConfig();
// Do not test `.data.js` files
config.testPathIgnorePatterns = [
...config.testPathIgnorePatterns,
'/.*.data.js$/'
];
module.exports = config;
Tests
Any parameter passed to the test
command is passed down to Jest.
$ npm t
$ npm t -- --watch # To run watch mode
License
Released under the MIT License.