@roastery-capsules/api-response-mapper

Elysia plugin that automatically maps entity responses to DTOs for the Roastery CMS ecosystem.

Overview

baristaResponseMapper is an Elysia plugin that intercepts all responses after they are handled and automatically converts @roastery/beans Entity instances (and arrays of them) to plain DTOs via Mapper.toDTO. It also preserves the original HTTP status code when the response is wrapped in an ElysiaCustomStatusResponse.

Technologies

Tool	Purpose
Elysia	HTTP framework and plugin system
@roastery/barista	Elysia factory used across the Roastery ecosystem
@roastery/beans	Entity and Mapper base classes
Bun	Runtime, test runner, and package manager
tsup	Bundling to ESM + CJS with .d.ts generation

Installation

bun add @roastery-capsules/api-response-mapper

Peer dependencies:

bun add @roastery/barista @roastery/beans

Usage

Register the plugin on your Elysia app:

import { Elysia } from "elysia";
import { baristaResponseMapper } from "@roastery-capsules/api-response-mapper";

const app = new Elysia()
  .use(baristaResponseMapper)
  .get("/users/:id", ({ params }) => {
    return new UserEntity({ id: params.id, name: "Alan" });
  })
  .listen(3000);

The plugin registers a global onAfterHandle hook, so all routes and sub-apps are covered automatically.

What it does

• If the response is an Entity, it is replaced with Mapper.toDTO(entity).
• If the response is an array where the first element is an Entity, every item is mapped with Mapper.toDTO.
• If the response is wrapped in ElysiaCustomStatusResponse (e.g. returned via status(201, entity)), it is unwrapped before mapping and the original status code is preserved.
• Any other response type is left untouched.

Development

# Run tests
bun run test:unit

# Run tests with coverage
bun run test:coverage

# Build for distribution
bun run build

# Check for unused exports and dependencies
bun run knip

# Full setup (build + bun link)
bun run setup

License

MIT