@fin.cx/mt940 is a small TypeScript wrapper around mt940-js for parsing MT940 electronic bank statement data into structured JavaScript objects. It accepts MT940 content as a string or ArrayBufferLike, returns the parsed statement model from mt940-js, and includes a BUNQ-specific account id normalization step for statements whose reference number is BUNQ BV.

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Install

pnpm add @fin.cx/mt940

What It Does

Parses complete MT940 file content from a string with parseMt940FileString().
Parses MT940 data from an ArrayBufferLike with parseMt940Buffer().
Returns the statement, balance, and transaction objects produced by mt940-js.
Normalizes BUNQ statement account ids by stripping the trailing currency segment from accountId.
Works with modern ESM TypeScript projects.

Basic Usage

import { Mt940Parser } from '@fin.cx/mt940';

const mt940Content = `:20:STARTUMS
:25:NL91ABNA0417164300
:28C:00000
:60F:C180605EUR0,00
:61:1806050605D5,00NTRFNONREF//123
:86:/TRCD/001/NAME/Test transaction
:62F:C180605EUR5,00
-`;

const parser = new Mt940Parser();
const statements = await parser.parseMt940FileString(mt940Content);

console.log(statements[0].accountId); // NL91ABNA0417164300
console.log(statements[0].transactions[0].amount); // 5

Parsing File Data In Node.js

parseMt940Buffer() expects an ArrayBufferLike. When reading with Node.js, slice the underlying ArrayBuffer to the actual byte range of the Buffer.

import { readFile } from 'node:fs/promises';
import { Mt940Parser } from '@fin.cx/mt940';

const parser = new Mt940Parser();
const fileBuffer = await readFile('./statement.mt940');
const arrayBuffer = fileBuffer.buffer.slice(
  fileBuffer.byteOffset,
  fileBuffer.byteOffset + fileBuffer.byteLength
);

const statements = await parser.parseMt940Buffer(arrayBuffer);
console.log(statements);

Parsing Browser File Uploads

Browser File objects already expose arrayBuffer(), so uploaded MT940 files can be parsed without Node.js APIs.

import { Mt940Parser } from '@fin.cx/mt940';

const parser = new Mt940Parser();

async function parseUploadedMt940(file: File) {
  const statements = await parser.parseMt940Buffer(await file.arrayBuffer());
  return statements;
}

Returned Data

The returned statement objects come from mt940-js and include fields such as:

referenceNumber
accountId
number
openingBalance
closingBalance
transactions

Transaction objects include fields such as:

id
code
isCredit
isExpense
currency
description
amount
valueDate
entryDate
customerReference
bankReference

BUNQ Account Id Normalization

Some BUNQ MT940 exports provide an accountId with a trailing currency segment, for example NL91BUNQ1234567890 EUR. When a parsed statement has referenceNumber === 'BUNQ BV', this module rewrites that accountId to NL91BUNQ1234567890.

const statements = await parser.parseMt940FileString(bunqMt940Content);
console.log(statements[0].accountId); // NL91BUNQ1234567890

Development

pnpm install
pnpm test
pnpm run build

License and Legal Information

This repository contains open-source code licensed under the MIT License. A copy of the license can be found in the LICENSE file.

Please note: The MIT License does not grant permission to use the trade names, trademarks, service marks, or product names of the project, except as required for reasonable and customary use in describing the origin of the work and reproducing the content of the NOTICE file.

Trademarks

This project is owned and maintained by Task Venture Capital GmbH. The names and logos associated with Task Venture Capital GmbH and any related products or services are trademarks of Task Venture Capital GmbH or third parties, and are not included within the scope of the MIT license granted herein.

Use of these trademarks must comply with Task Venture Capital GmbH's Trademark Guidelines or the guidelines of the respective third-party owners, and any usage must be approved in writing. Third-party trademarks used herein are the property of their respective owners and used only in a descriptive manner, e.g. for an implementation of an API or similar.

readme.md

@fin.cx/mt940