This package contains a set of jest configs that set up runners for running unit tests, integration tests, eslint, and prettier.

Installing

Use the package manager of your choice to install:

• npm: npm install --save-dev @cprussin/jest-config
• pnpm: pnpm add -D @cprussin/jest-config
• yarn: yarn add -D @cprussin/jest-config

Usage

1. Set up your jest.config.js, for example:

export { base as default } from "@cprussin/jest-config";
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2. Run jest to run format checks, lint checks, unit tests, and integration tests, or use --selectProjects to run a subset of checks.

3. Add scripts to your package.json if you'd like. For instance:

{
  "scripts": {
    "test:format": "jest --selectProjects format",
    "test:integration": "jest --selectProjects integration",
    "test:lint": "jest --selectProjects lint",
    "test:unit": "jest --coverage --selectProjects unit"
  }
}
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Projects

Configurations exported with this package will set up the following jest projects:

• format: Check code style with prettier using jest-runner-prettier.
• integration: Tests that run out of the integration-tests directory. Functionally not much different than unit, but you can have a separate configuration, different pipeline dependencies, etc.
• lint: Run eslint checks using jest-runner-eslint.
• unit: Need I say more?

Running jest will run all four projects. You can run a subset of the projects using jest's --selectProjects argument, as usual.

Options

If you need to, you can extend or wrap the configs generated here by calling the config you want and passing an object as an argument that describes your modifications. The object can have any combination of the following keys:

• format: Specify extensions or wrappers for the format project.
• global: Specify extensions or wrappers for the top-level jest config.
• integration: Specify extensions or wrappers for the integration project.
• lint: Specify extensions or wrappers for the lint project.
• unit: Specify extensions or wrappers for the unit project.

The value for each of those keys should be an object containing either or both of config, an object whose values will be spread into the relevant project or global config, and wrapper, a function that should take the config and return a promise containing the final config. For example:

import { base } from "@cprussin/jest-config";

export default base({
  global: {
    wrapper: async (oldGlobalConfig) => doSomethingAsyncWith(oldGlobalConfig),
    config: {
      passWithNoTests: true,
    },
  },
  unit: {
    wrapper: async (oldUnitConfig) => doSomethingAsyncWith(oldUnitConfig),
  },
  format: {
    config: {
      testPathIgnorePatterns: ["foo/*"],
    },
  },
});
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Note that the extensions will be spread before calling the wrapper (so the values in the config option will be present in the argument to the wrapper).