Type Reflection

Compile-time type introspection with zero runtime overhead. Examine types, extract metadata, and generate validators.

Quick Start

npm install @typesugar/reflect

import { typeInfo, fieldNames, validator } from "@typesugar/reflect";

interface User {
  id: number;
  name: string;
  email?: string;
}

const fields = fieldNames<User>();
// Compiles to: ["id", "name", "email"]

const validateUser = validator<User>();
// Generates a runtime validator from the type

Features

typeInfo<T>() — Get Type Metadata

const meta = typeInfo<User>();
// Compiles to:
// {
//   name: "User",
//   kind: "interface",
//   fields: [
//     { name: "id", type: "number", optional: false },
//     { name: "name", type: "string", optional: false },
//     { name: "email", type: "string", optional: true },
//   ]
// }

fieldNames<T>() — Get Field Names

const fields = fieldNames<User>();
// Compiles to: ["id", "name", "email"]

validator<T>() — Generate Runtime Validator

const validateUser = validator<User>();

const result = validateUser(unknownData);
if (result.success) {
  console.log(result.value.name); // Type-safe access
} else {
  console.log(result.errors);
}

@reflect — Enable Reflection Metadata

@reflect
interface User {
  id: number;
  name: string;
}

// Generates alongside the interface:
export const __User_meta__ = { /* metadata */ };

Learn More

• API Reference
• Package README