code-api-web/src/packages/fastify-send-data/index.ts

import { FastifyInstance, FastifyReply } from 'fastify'
import fp from 'fastify-plugin'
import { constants } from 'http2'

export interface ResponseDataInterface<T extends unknown = undefined> {
	statusCode: number
	statusMessage?: string
	body?: T extends undefined ? undefined : { data: T }
}

const BLANK_BODY_STATUS_CODES = [
	constants.HTTP_STATUS_NO_CONTENT,
	constants.HTTP_STATUS_RESET_CONTENT,
]

const fastifySendData = async (app: FastifyInstance) => {
	const sendDataKey = 'sendData' as const
	app.decorateReply(sendDataKey, function reply<T extends ResponseDataInterface>(this: FastifyReply, data: T) {
		this.status(data.statusCode)
		if (data.statusMessage) {
			this.raw.statusMessage = data.statusMessage
		}
		if (!BLANK_BODY_STATUS_CODES.includes(data.statusCode)) {
			this.send(data.body)
			return
		}
		this.removeHeader('content-type')
		this.removeHeader('content-length')
		this.send()
	})
}

type SendData<O extends unknown = unknown, T extends ResponseDataInterface<O> = ResponseDataInterface<O>> = (data: T) => void

declare module 'fastify' {
	interface FastifyReply {
		sendData: SendData
	}
}

export const HttpResponse = <T extends unknown = undefined>(
	statusCode = constants.HTTP_STATUS_OK,
	statusMessage?: string,
) => class HttpResponseData {
	readonly statusCode = statusCode
	readonly statusMessage = statusMessage
	readonly body?: { data: T }

	constructor(data?: T) {
		if (data && !BLANK_BODY_STATUS_CODES.includes(statusCode)) {
			this.body = {
				data,
			}
		}
	}
}

export default fp(fastifySendData)