Function: parseSn()

parseSn(rep, enc): SN | undefined

Parse an HL7 v2 SN repetition into a structured SN, or undefined when the field carries no usable structured-numeric content (empty, or so malformed that no comparator, number, or separator can be recovered). Components are returned verbatim (already decoded by the tokenizer); num1/num2 use strict Number() parsing.

Fail-safe: a non-operator value in the comparator slot (SN.1) is dropped rather than surfaced as a relation, and a non-numeric SN.2/SN.4 becomes undefined: the parser never emits a confident wrong comparator or number.

Parameters

rep

RawRepetition

enc

EncodingCharacters

Returns

SN | undefined

Example

import { parseSn, DEFAULT_ENCODING_CHARACTERS } from "@cosyte/hl7";
const rep = { components: [
  { subcomponents: [">"] },
  { subcomponents: ["90"] },
] };
const sn = parseSn(rep, DEFAULT_ENCODING_CHARACTERS);
console.log(sn?.comparator, sn?.num1); // ">" 90