msp-parser

Parse the mass .msp format.

It is being used for the MassBank and NIST database releases.

Installation

$ npm i msp-parser

This package is ESM-only. CommonJS consumers need Node.js ≥ 20.19, ≥ 22.12 or any 24.x and later (where require() of ESM works), or should migrate to import.

Usage

parseMSP accepts the content of a .msp file as a string, an ArrayBuffer or a typed array, and returns one MeasurementXY per entry: meta holds the Key: value header lines and variables.x / variables.y hold the m/z and relative intensity of the peaks.

import { parseMSP } from 'msp-parser';

const result = parseMSP(mspText);

// result[0].meta.Name -> 'Pyrophen'
// result[0].variables.x.data -> [91.0542, 125.0233, ...]
// result[0].variables.y.data -> [245, 999, ...]

A field that appears several times in one entry — Synon is the usual case — is collected into an array, in the order it was encountered, so no value is lost.

// result[1].meta.Synon -> ['F2 Toxin', '(2E,11S)-15,17-dihydroxy-...']

Iterating over a large library

A NIST release holds more than 50000 spectra per file. mspIterator yields the entries one at a time instead of building the whole array:

import { mspIterator } from 'msp-parser';

for (const entry of mspIterator(mspText)) {
  console.log(entry.meta.Name, entry.variables.x.data.length);
}

Dialects

Both layouts of the peak list are supported: one pair per line as MassBank writes it (91.0542 245), and several pairs packed on one line separated by semicolons as NIST writes it (12 108; 13 229; 14 999;).

NIST also packs the two registry numbers on a single line; they are returned as two separate fields:

CAS#: 1333-74-0;  NIST#: 245692

// entry.meta['CAS#']  -> '1333-74-0'
// entry.meta['NIST#'] -> '245692'

Only a semicolon followed by something shaped like a field label starts a new field, so a value that merely contains semicolons — such as the extra CAS numbers NIST stores as Synon: $:24156457-45-3; 263005-65-8 — is kept whole. Keys are split on their first colon, so a value containing a colon (a name such as 14,15:21,23-diepoxy-...) is preserved.

License

MIT