@stryker-mutator/core

StrykerJS

Professor X: For someone who hates mutants... you certainly keep some strange company. William Stryker: Oh, they serve their purpose... as long as they can be controlled.

Introduction

For an introduction to mutation testing and StrykerJS features, see stryker-mutator.io.

Getting started

Please follow the quickstart on the website.

For small js projects, you can try the following command:

npm install --save-dev @stryker-mutator/core
# Only for small projects:
npx stryker run

It will run stryker with default values:

• Uses npm test as your test command
• Searches for files to mutate in the lib and src directories

Usage

$ npx stryker <command> [options] [configFile]

See usage on stryker-mutator.io

Supported mutators

See our website for the list of currently supported mutators.

Configuration

See configuration on stryker-mutator.io.

Programmatic use

Stryker can also be used programmatically from nodejs. It exports 2 classes for you to use: Stryker and StrykerCli.

import { Stryker, StrykerCli } from '@stryker-mutator/core';

Both classes can be used to run Stryker. The main difference is that Stryker is a slightly more low-level approach, while StrykerCli is the straight up CLI api.

In this example you can see how to use both.

async function main() {
  // Runs Stryker as if it was called directly from the cli. Not even returns a promise, it assumes to be allowed to call `process.exit`.
  new StrykerCli(process.argv /* RAW argv array */ ).run(); 

  // Runs Stryker, will not assume to be allowed to exit the process.
  const stryker = new Stryker({ concurrency: 4 } /* Partial Stryker options object */ );
  const mutantResults = await stryker.runMutationTest();
  // mutantResults or rejected with an error.
}

Stryker is written in TypeScript, so it is recommended to use Stryker as well to get the best developer experience.

Changelog

5.5.0 (2021-11-23)

Bug Fixes

• instrumenter: don't mutate TS generics (#3268) (88d6eaf)
• logging: don't log log4js category to file as well (31609a5)
• util: clear require.cache behavior on case-insensitive file systems (#3194) (39e3d86)

Features

• checkers: allow custom checker node args (#3179) (82c4435)
• cli: display suggestions on error (#3216) (9ed98e8)
• config: Add link to docs when generating a custom config (#3235) (7c999b8)
• hit limit: infinite loop prevention in jasmine-runner (#3199) (bc792e0)
• hit limit: infinite loop prevention in mocha-runner (f5a7d1d)
• html: new diff-view when selecting mutants (#3263) (8b253ee)
• init: add buildCommand question when running (#3213) (b9d5980)
• jest-runner: support --findRelatedTests in dry run (#3234) (b2e4584)
• mutators: Implement missing AssignmentOperatorMutator (#3203) (95b694b)