infer-dos

A TypeScript tool to detect DurableObject classes in your codebase. Analyzes TypeScript files and identifies exported classes that extend or implement DurableObject, including transitive inheritance.

Installation

npm install infer-dos

CLI Usage

npx infer-dos <input-file>

Output: JSON array of DurableObject class names

Examples

See fixtures/ directory for example inputs and expected outputs. Run npm test to verify all test cases.

Programmatic Usage

import { getDurableObjectClassNames } from "infer-dos";

const classNames = getDurableObjectClassNames("./src/my-file.ts");
console.log(classNames); // ["MyDurableObject", "MyServer"]

How It Works

• Uses your project's tsconfig.json for accurate type resolution
• Detects classes that directly extend DurableObject from cloudflare:workers
• Detects classes that implement the DurableObject interface
• Follows inheritance chains to detect transitive DurableObject classes
• Handles generic types and complex type hierarchies

Supported Patterns

// Direct extends
export class MyClass extends DurableObject {}

// Implements interface
export class MyClass implements DurableObject {}

// Transitive extends (Server, Agent, Actor, etc.)
export class MyServer extends Server {} // Server extends DurableObject
export class MyAgent extends Agent {} // Agent extends Server extends DurableObject
export class MyActor extends Actor {} // Actor extends DurableObject

Next up:

• maybe a vite plugin? so you'd never need to run the CLI
• using the clouflare api to infer migrations as well