HL7v2 toolkit

Pre-configured unified processor that parses, annotates, decodes, lints, and serializes HL7v2 messages.

What it does

@glion/hl7v2 exports parseHL7v2, a frozen unified processor assembled from the Glion plugin set. Feeding it an HL7v2 string returns a VFile whose result is the JSON serialization, whose tree is the transformed AST, and whose messages list holds every lint diagnostic gathered along the way. Use it when you want the full pipeline; reach for individual plugins when you need a different composition.

Install

npm install @glion/hl7v2

Use

import { parseHL7v2 } from "@glion/hl7v2";

const file = await parseHL7v2.process(
  "MSH|^~\\&|SENDER||RECEIVER||20241201||ADT^A01|MSG123|P|2.5\rPID|1||12345"
);

console.log(file.messages); // lint diagnostics (warnings + errors)
console.log(String(file)); // JSON output

The processor is frozen. To extend it, call .use(...) on a fresh unified() instance composed of the plugins you need.

API

`parseHL7v2`

The frozen processor exported by this package. Its type is Processor<Root, Root, Root, Root, string> — it parses strings into an HL7v2 AST (Root), transforms the tree, and compiles it back to a JSON string via @glion/jsonify.

import type { Processor } from "unified";
import type { Root } from "@glion/ast";

export const parseHL7v2: Processor<Root, Root, Root, Root, string>;

Common methods inherited from unified:

Method	Description
`parseHL7v2.process(input)`	Parse, transform, and compile. Returns a `Promise<VFile>`.
`parseHL7v2.parse(input)`	Parse only. Returns a `Root` AST without running transforms or the compiler.
`parseHL7v2.run(tree)`	Run the transform phase on a pre-parsed tree. Returns a `Promise<Root>`.
`parseHL7v2.stringify(tree)`	Compile a tree to the JSON output without re-running transforms.

AST

The syntax tree produced by parseHL7v2 is defined in @glion/ast. Every node is a unist node; see the AST README for the full hierarchy.

Pipeline

parseHL7v2 composes six plugins in this order (see packages/hl7v2/src/index.ts):

import { unified } from "unified";
import { hl7v2Parser } from "@glion/parser";
import { hl7v2AnnotateDelimiters } from "@glion/annotate-delimiters";
import { hl7v2DecodeEscapes } from "@glion/decode-escapes";
import hl7v2PresetLintRecommended from "@glion/preset-lint-recommended";
import hl7v2PresetLintProfileRecommended from "@glion/preset-lint-profile-recommended";
import { hl7v2Jsonify } from "@glion/jsonify";

export const parseHL7v2 = unified()
  .use(hl7v2Parser)
  .use(hl7v2AnnotateDelimiters)
  .use(hl7v2DecodeEscapes)
  .use(hl7v2PresetLintRecommended)
  .use(hl7v2PresetLintProfileRecommended)
  .use(hl7v2Jsonify)
  .freeze();

Stage	Package	What it contributes
`hl7v2Parser`	`@glion/parser`	Tokenizes HL7v2 text into a `Root` AST following the `@glion/ast` spec.
`hl7v2AnnotateDelimiters`	`@glion/annotate-delimiters`	Resolves delimiters from MSH-1/MSH-2 and stores them on `file.data.delimiters`.
`hl7v2DecodeEscapes`	`@glion/decode-escapes`	Decodes HL7 escape sequences (`\F\`, `\S\`, `\Xdddd\`, `\.br\`, …) into subcomponent values.
`hl7v2PresetLintRecommended`	`@glion/preset-lint-recommended`	Applies the general lint rule set (structural checks, required segments, version).
`hl7v2PresetLintProfileRecommended`	`@glion/preset-lint-profile-recommended`	Applies profile-aware lint rules (field definitions, datatypes, table values).
`hl7v2Jsonify`	`@glion/jsonify`	Compiles the transformed tree to the simplified JSON representation.

To build your own pipeline, import the plugins directly and compose them on a fresh unified() instance.

Custom pipelines

import { unified } from "unified";
import { hl7v2Parser } from "@glion/parser";
import { hl7v2ToHl7v2 } from "@glion/to-hl7v2";

// Parse-and-reserialize (round-trip)
const roundtrip = unified().use(hl7v2Parser).use(hl7v2ToHl7v2).freeze();

Any unified plugin that operates on the @glion/ast tree can be slotted in — custom lints, annotators, transformers, or alternative compilers like @glion/to-hl7v2.

HL7v2 toolkit

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