Field repetition

Lint rule that flags non-repeatable fields with multiple repetitions.

What it does

Flags fields that contain more than one repetition (delimited by ~) when the HL7v2 profile for the message's version declares repeatable: false for that field. The rule reads profile context attached by @glion/annotate-profile-context. A single repetition is always valid regardless of the repeatable flag; only 2+ repetitions on a non-repeatable field are reported. Segments without a known profile are silently skipped.

Install

npm install @glion/lint-profile-field-repetition

Use

import { hl7v2AnnotateProfileContext } from "@glion/annotate-profile-context";
import { hl7v2Parser } from "@glion/parser";
import hl7v2LintFieldRepetition from "@glion/lint-profile-field-repetition";
import { unified } from "unified";
import { reporter } from "vfile-reporter";

const message = [
  "MSH|^~\\&|SENDER|FAC|RECV|RFAC|20250601120000||ADT^A01^ADT_A01|MSG00001|P|2.5",
  "PID|1||PATID1234^^^HOSP^MR||DOE^JANE||19800101|F",
].join("\r");

const file = await unified()
  .use(hl7v2Parser)
  .use(hl7v2AnnotateProfileContext)
  .use(hl7v2LintFieldRepetition)
  .process(message);

console.error(reporter([file]));

API

unified().use(hl7v2LintFieldRepetition)

A unified lint rule plugin. Takes no options.

Reads file.data.profile. For each field under a segment with a known profile it looks up the field entry by sequence. If the field's profile sets repeatable: false and the AST has more than one repetition, the rule emits one message for that field.

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

declare const hl7v2LintFieldRepetition: Plugin<[], Root>;
export default hl7v2LintFieldRepetition;

What it checks

This rule flags fields with multiple ~-delimited repetitions when the profile marks the field as non-repeatable. For example, PID-7 (Date of Birth) is not repeatable in v2.5.

Valid

PID-7 carries a single Date of Birth:

MSH|^~\&|SENDER|FAC|RECV|RFAC|20250601120000||ADT^A01^ADT_A01|MSG00001|P|2.5
PID|1||PATID1234^^^HOSP^MR||DOE^JANE||19800101|F

Invalid

PID-7 carries two ~-separated values, which violates the v2.5 profile for the PID-7 field:

MSH|^~\&|SENDER|FAC|RECV|RFAC|20250601120000||ADT^A01^ADT_A01|MSG00001|P|2.5
PID|1||PATID1234^^^HOSP^MR||DOE^JANE||19800101~19800102|F

Reported message:

Field PID-7 (Date/Time of Birth) is not repeatable but has 2 repetitions

When the field name is available in the profile it appears in parentheses after the position. The reported count equals the number of repetitions present in the field.