Stryker - Static Code Analysis

Stryker: A Comprehensive Static Code Analysis Tool for TypeScript and JavaScript

Introduction

Stryker is a powerful static code analysis tool that helps developers identify and fix potential bugs, vulnerabilities, and coding violations in TypeScript and JavaScript code. It is based on Open Source rules and plugins, making it highly customisable and extensible. Stryker can be integrated into CI/CD pipelines, ensuring that code is analyzed and optimised before deployment.

Benefits of Using Stryker

There are many benefits to using Stryker, including:

Improved Code Quality: Stryker helps to identify and fix potential bugs and vulnerabilities, improving the overall quality of your TypeScript and JavaScript code.
Reduced Risk of Security Issues: Stryker can identify security vulnerabilities in your code, helping to reduce the risk of them being exploited in production.
Early Error Detection: Stryker catches potential errors early in the development process, saving you time and effort by preventing them from being introduced into production.
Streamlined Development Workflow: Stryker can be integrated into your development workflow, ensuring your code is automatically analysed and optimised.
Consistent Code Standards: Stryker enforces consistent code standards across the codebase, promoting maintainability and readability.

Features of Stryker

Stryker offers a wide range of features, including:

Static Code Analysis: Stryker analyzes TypeScript and JavaScript code to identify potential bugs, vulnerabilities, and coding violations.
Customisable Rules: Stryker supports a wide range of Open Source rules and plugins, allowing you to customise the analysis to your specific needs.
Integration with CI/CD Pipelines: Stryker can be integrated with CI/CD pipelines, ensuring that code is analyzed and optimised before deployment.
Visual Reporting: Stryker generates detailed reports that identify potential issues and provide recommendations for remediation.
Integration with Code Editors: Stryker integrates with code editors, providing real-time feedback on code violations.

Installing Stryker

To install Stryker, you can follow these steps:

Open your project’s root directory in a terminal window.
Run the following command:

npm install -D stryker

This will install Stryker as a development dependency.

Configuring Stryker

Once you have installed Stryker, you need to configure it to point to your project’s configuration file. This file defines the rules, plugins, and other settings for Stryker. To do this:

Create a stryker.json file in your project’s root directory.
Add the following configuration to the stryker.json file:

{
  "project": "path/to/project/directory",
  "rules": {
    "no-unused-vars": true
  },
  "plugins": ["@stryker/typescript"]
}

This configuration will run the no-unused-vars rule and use the @stryker/typescript plugin. You can customise the configuration by adding or removing rules and plugins.

Init command

The stryker init command is a powerful tool for starting with Stryker, a static code analysis tool for TypeScript and JavaScript. It automates setting up Stryker for a new project, ensuring that you have all the necessary configuration files and plugins in place.

What the Stryker init Command Does

The stryker init command performs the following tasks:

Creates a stryker.json configuration file: This file defines the rules, plugins, and other settings for Stryker.
Installs the @stryker/core package as a development dependency: This package provides the core functionality of Stryker.
Optionally, installs additional Stryker plugins: These plugins provide additional functionality, such as code coverage or mutation testing.
Generates a tsconfig.json file if one does not exist: This file defines the compilation options for TypeScript files.
Formats the project’s TypeScript and JavaScript code: This ensures that the code is consistent with the project’s style guide.

Using the Stryker init Command

To use the stryker init command, open a terminal window and navigate to the root directory of your TypeScript or JavaScript project. Then, run the following command:

npx stryker init

This will prompt you for a few questions about your project, including the name of your project and the path to your TypeScript or JavaScript files. The command will then generate the necessary configuration files and plugins for your project.

Running Stryker After Initialization

Once you have initialized Stryker with the stryker init command, you can run Stryker to analyze your code. To do this, open a terminal window and navigate to the root directory of your project.

Using Stryker

Once you have configured Stryker, you can analyze your code. To do this, you can run the following command:

npx stryker

This will start Stryker and generate a report identifying your code’s potential bugs, vulnerabilities, and coding violations. The report will be written to the output/report.html file in the root directory of your project.

Examples of Stryker Reports

Here are some examples of Stryker reports:

Code Quality Report: This report identifies potential bugs and vulnerabilities in your code.
Security Report: This report identifies security vulnerabilities in your code.
Style Guide Report: This report identifies violations of your coding style guide.

Stryker also provides detailed reports for each rule that is run. These reports provide information about the rule, the location of the violation, and the severity of the violation.

Example Reports

Here is an example of a Stryker report that identifies a potential bug:

{
  "code": "1234",
  "level": "error",
  "message": "Unused variable",
  "ruleId": "no-unused-vars",
  "filename": "myfile.ts",
  "line": 10,
  "column": 10,
  "source": "typescript"
}

This report indicates that a variable named myVar is declared but never used in the file myfile.ts. This is a potential bug, as the variable could be leaking memory.

Here is an example of a Stryker report that identifies a potential security vulnerability:

{
  "code": "5678",
  "level": "warning",
  "message": "Potential XSS vulnerability",
  "ruleId": "xss-no-unsafe-html",
  "filename": "myfile.ts",
  "line": 20,
  "column": 10,
  "source": "typescript"
}

This report indicates that a string containing user input is being directly inserted into a HTML DOM element without adequately sanitising. This could lead to a cross-site scripting (XSS) vulnerability, allowing attackers to inject malicious code into the application.

Conclusion

Stryker is a powerful tool that can help you improve the quality, security, and maintainability of your TypeScript and JavaScript code. Using Stryker, you can help ensure that your code is free of bugs, vulnerabilities, and coding violations.

Stryker – Static Code Analysis