Field max length

Lint rule that reports a field value longer than HL7v2 allows.

What it does

Flags a field value longer than the maximum length the HL7v2 standard gives that field in the message's version. Each repetition of a field is measured on its own, and delimiters (^, &) are not counted. It needs the plugins @glion/annotate-profile-context and @glion/annotate-profile-fields to run before it; @glion/preset-lint-profile-recommended includes them.

Install

npm install @glion/lint-profile-field-max-length

Use

import { hl7v2AnnotateProfileContext } from "@glion/annotate-profile-context";
import { hl7v2AnnotateProfileFields } from "@glion/annotate-profile-fields";
import hl7v2LintFieldMaxLength from "@glion/lint-profile-field-max-length";
import { parseHL7v2 } from "@glion/parser";
import { unified } from "unified";
import { VFile } from "vfile";
import { reporter } from "vfile-reporter";

const message = [
  "MSH|^~\\&|SENDER|FAC|RECV|RFAC|20250601120000||ADT^A01^ADT_A01|MSG0000000000000000000000001|P|2.5",
  "PID|1||PATID1234^^^HOSP^MR||DOE^JANE||19800101|F",
].join("\r");

const file = new VFile();
await unified()
  .use(hl7v2AnnotateProfileContext)
  .use(hl7v2AnnotateProfileFields)
  .use(hl7v2LintFieldMaxLength)
  .run(parseHL7v2(message), file);

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

API

`unified().use(hl7v2LintFieldMaxLength)`

A unified lint rule plugin. Takes no options. Reports one message for each field repetition over the limit.

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

declare const hl7v2LintFieldMaxLength: Plugin<[], Root>;
export default hl7v2LintFieldMaxLength;

What it checks

Each repetition of a field is at most as long as the field's maximum length in the message's version. For example, MSH-10 (Message Control ID) allows 20 characters in v2.5.

Valid

MSH-10 has 8 characters:

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

Invalid

MSH-10 has 28 characters:

MSH|^~\&|SENDER|FAC|RECV|RFAC|20250601120000||ADT^A01^ADT_A01|MSG0000000000000000000000001|P|2.5
PID|1||PATID1234^^^HOSP^MR||DOE^JANE||19800101|F

Reported message:

The value is 28 characters long; the field allows at most 20 characters.

A composite value such as DOE^JANE counts as 7 characters, not 8.

Field max length

On this page