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Version: v0.0.3

Installation

@cosyte/mllp is a zero-dependency TypeScript MLLP client + server for Node.js. It ships dual ESM + CJS builds with per-condition type declarations, so it works from either module system without configuration. It is transport, not parsing. It moves HL7 v2 bytes over TCP and never inspects the payload.

Status: published on npm and public, still pre-alpha on the cosyte 0.0.x-until-first-alpha ladder, so the API can change with no deprecation cycle. The npm install @cosyte/mllp command below is live, not aspirational.

Prerequisites​

  • Node.js >= 22. The whole @cosyte/* suite targets ES2023 / Node 22+. This package leans on Symbol.asyncDispose and AbortSignal on its public surface, both 2026 Node baseline.
  • A package manager: pnpm, npm, or yarn.
  • No runtime dependencies. The client, server, and framing are Node stdlib only (net, tls, stream, events, buffer, timers).

Install​

npm install @cosyte/mllp

The optional @cosyte/hl7 peer​

@cosyte/hl7 is an optional peer dependency, needed only if you use the ack-from-hl7 subpath (which builds spec-correct ACKs by delegating the parsing to @cosyte/hl7). Everything else (framing, the client, the server, TLS, the in-memory transport) works without it. Install it only if you reach for that subpath:

npm install @cosyte/hl7

Calling ack-from-hl7 without the peer installed throws a typed MllpPeerMissingError, not a bare module-not-found.

Smoke test​

Confirm the package resolves and its version symbol is present:

import { VERSION } from "@cosyte/mllp";

typeof VERSION; // => "string"

If that resolves, the install is good. Head to the Quickstart.

Module systems​

@cosyte/mllp is "type": "module" and exposes both conditions, so both of these resolve to the right build without extra configuration:

// ESM / TypeScript
import { MllpClient, MllpServer } from "@cosyte/mllp";
// CommonJS
const { MllpClient, MllpServer } = require("@cosyte/mllp");

The types are published per-condition (.d.ts for import, .d.cts for require) and gated by attw on every release, across all three subpaths (root, /testing, /ack-from-hl7), so editor IntelliSense matches the build you actually load.