@typesugar/mapper

Zero-cost compile-time object mapping and transformation for Typesugar. Inspired by Scala's Chimney, but fully integrated into the TypeScript ecosystem with zero runtime overhead.

Features

• Zero-cost: All transformations are evaluated at compile time and inlined as direct property access.
• Type-safe: Compile-time validation of all mappings. Fails the build if a target field is not mapped.
• No decorators needed: Works with plain interfaces and types.

Usage

import { transformInto } from "@typesugar/mapper";

interface User {
  first_name: string;
  last_name: string;
  age: number;
}

interface UserDTO {
  firstName: string;
  lastName: string;
  age: number;
  role: string;
}

const user: User = { first_name: "John", last_name: "Doe", age: 30 };

const dto = transformInto<User, UserDTO>(user, {
  rename: {
    firstName: "first_name",
    lastName: "last_name",
  },
  const: {
    role: "user",
  },
});

// dto is { firstName: "John", lastName: "Doe", age: 30, role: "user" }
// This compiles directly to an object literal with no function call overhead!