Code Salmon Documentation

A TypeScript backend dev's most trusted gadget against the dastardly silent assassins known only as REST API Contract Drift.

What is Code Salmon?

Code Salmon is a CLI tool that scans TypeScript projects for REST API calls. Once identified, it fires those calls to create a baseline JSON snapshot for future comparisons—your bulletproof vest against silent API drift.

• Scan your project's REST API calls
• Compare results to your original baseline
• Adjust code to reflect any API changes

Problem Solved

External APIs evolve. When they do, your application might silently break. Code Salmon stops that by:

• Detecting contract drift early
• Tracking every endpoint you depend on

Features

• Scans .ts files for fetch() calls
• Extracts API URLs and environment keys
• Fetches and saves baseline responses in JSON
• Compares future responses to detect structural drift
• Reports drift directly in the terminal

Configuration Tips

• Ensure a valid .env file exists with relevant API keys
• Customize scan targets via tsconfig.json

Installation & Usage

npm install codesalmon

To generate your initial baseline:

scanSalmon

To check for contract drift later:

swimSalmon

*Pro Tip: For meaningful contract drift, wait days or weeks between scans to observe real API changes.*

Contract Drift Report

When you run swimSalmon, the CLI outputs a detailed report highlighting any changes to API responses.

Possible Report Outputs

• Changed at: Indicates fields with value/type changes
• Addition at: Shows where new key/value pairs were added
• Removed at: Flags missing fields from the original baseline
• Unhandled Change Type: Catches unknown or deeply restructured responses