---
title: "Stress-test JavaScript and TypeScript test suites with mutation testing before risky changes ship with StrykerJS"
description: "Run mutation testing against JS or TS projects to find tests that still pass when real defects are introduced."
verification: "listed"
source: "https://github.com/stryker-mutator/stryker-js"
author: "Stryker Mutator"
publisher_type: "organization"
category:
  - "Code Quality & Review"
framework:
  - "Multi-Framework"
tool_ecosystem:
  github_repo: "stryker-mutator/stryker-js"
  github_stars: 2828
  npm_package: "@stryker-mutator/core"
  npm_weekly_downloads: 1537001
---

# Stress-test JavaScript and TypeScript test suites with mutation testing before risky changes ship with StrykerJS

Run mutation testing against JS or TS projects to find tests that still pass when real defects are introduced.

## Prerequisites

Node.js, npm, a supported JavaScript or TypeScript test runner

## Installation

Choose whichever fits your setup:

1. Copy this skill folder into your local skills directory.
2. Clone the repo and symlink or copy the skill into your agent workspace.
3. Add the repo as a git submodule if you manage shared skills centrally.
4. Install it through your internal provisioning or packaging workflow.
5. Download the folder directly from GitHub and place it in your skills collection.

Install command or upstream instructions:

```
Install the core package with `npm install --save-dev @stryker-mutator/core`, run the Stryker initializer or config flow for your test runner, then execute Stryker as a pre-merge or pre-release mutation test step.
```

## Documentation

- https://stryker-mutator.io/

## Source

- [Agent Skill Exchange](https://agentskillexchange.com/skills/stress-test-javascript-and-typescript-test-suites-with-mutation-testing-before-risky-changes-ship-with-strykerjs/)