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accounted/lib/import/sie-parser.ts
T
Jakob Wennberg 0ba1db1c21 fix: skip BTRANS/RTRANS in SIE parser to prevent false balance errors (#63)
When Fortnox corrects a voucher, the SIE file contains #BTRANS (added)
and #RTRANS (removed) lines alongside #TRANS (final state). The parser
was summing all three, causing corrected vouchers to appear unbalanced.
Only #TRANS represents the final voucher state — BTRANS/RTRANS are
correction audit trail.

Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
2026-03-20 12:10:08 +01:00

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/**
* SIE File Parser
*
* Parses SIE (Standard Import Export) files, the Swedish standard format
* for accounting data exchange. Supports SIE1-SIE4 formats.
*
* SIE4 is the most complete format with full transaction history.
* SIE1 contains only year-end balances.
*
* Reference: https://sie.se/format/
*/
import type {
SIEType,
SIEEncoding,
SIEHeader,
SIEAccount,
SIEBalance,
SIEVoucher,
SIETransactionLine,
ParsedSIEFile,
ParseIssue,
ParseIssueSeverity,
ValidationResult,
} from './types'
// CP437 to UTF-8 mapping — full 0x80-0x9F range
// CP437 was the standard encoding for DOS/early Windows (used by SIE #FORMAT PC8)
const CP437_MAP: Record<number, string> = {
// 0x80-0x8F
0x80: 'Ç', // Ç
0x81: 'ü', // ü
0x82: 'é', // é
0x83: 'â', // â
0x84: 'ä', // ä
0x85: 'à', // à
0x86: 'å', // å
0x87: 'ç', // ç
0x88: 'ê', // ê
0x89: 'ë', // ë
0x8a: 'è', // è
0x8b: 'ï', // ï
0x8c: 'î', // î
0x8d: 'ì', // ì
0x8e: 'Ä', // Ä
0x8f: 'Å', // Å
// 0x90-0x9F
0x90: 'É', // É
0x91: 'æ', // æ
0x92: 'Æ', // Æ
0x93: 'ô', // ô
0x94: 'ö', // ö
0x95: 'ò', // ò
0x96: 'û', // û
0x97: 'ù', // ù
0x98: 'ÿ', // ÿ
0x99: 'Ö', // Ö
0x9a: 'Ü', // Ü
0x9b: 'ø', // ø (Norwegian)
0x9c: '£', // £
0x9d: 'Ø', // Ø (Norwegian)
0x9e: '×', // ×
0x9f: 'ƒ', // ƒ
}
// Windows-1252 bytes for Swedish characters (superset of ISO-8859-1)
// These bytes are NOT in the CP437 map, so they need separate detection.
const WIN1252_SWEDISH_BYTES = new Set([
0xe5, // å
0xe4, // ä
0xf6, // ö
0xc5, // Å
0xc4, // Ä
0xd6, // Ö
])
/**
* Detect the encoding of a SIE file by looking for Swedish characters.
*
* Strategy:
* 1. UTF-8 BOM → utf8
* 2. `#FORMAT PC8` in raw bytes → cp437 (SIE standard header for CP437)
* 3. Range-based discrimination: CP437 Swedish chars live in 0x80-0x9F,
* Windows-1252 Swedish chars live in 0xC0-0xFF. These ranges don't overlap,
* so presence in one range rules out the other.
* 4. UTF-8 multi-byte sequences (0xC3 + continuation) are detected with proper
* skipping of continuation bytes to avoid false CP437 counts.
*/
export function detectEncoding(buffer: ArrayBuffer): SIEEncoding {
const bytes = new Uint8Array(buffer)
// Check for UTF-8 BOM
if (bytes[0] === 0xef && bytes[1] === 0xbb && bytes[2] === 0xbf) {
return 'utf8'
}
// Check for #FORMAT PC8 in the first 500 bytes (ASCII-safe, works regardless of encoding)
const headerSize = Math.min(bytes.length, 500)
const FORMAT_PC8 = [0x23, 0x46, 0x4f, 0x52, 0x4d, 0x41, 0x54, 0x20, 0x50, 0x43, 0x38]
for (let i = 0; i <= headerSize - FORMAT_PC8.length; i++) {
let match = true
for (let j = 0; j < FORMAT_PC8.length; j++) {
if (bytes[i + j] !== FORMAT_PC8[j]) {
match = false
break
}
}
if (match) {
return 'cp437'
}
}
// Scan sample for encoding-specific byte ranges
const sampleSize = Math.min(bytes.length, 2000)
let cp437Count = 0 // Swedish chars in 0x80-0x9F (CP437 range)
let utf8Count = 0 // Valid UTF-8 multi-byte Swedish sequences
let win1252Count = 0 // Swedish chars in 0xC0-0xFF (Win-1252 range)
for (let i = 0; i < sampleSize; i++) {
const byte = bytes[i]
// Check for CP437 Swedish characters
if (CP437_MAP[byte]) {
cp437Count++
}
// Check for Windows-1252 Swedish characters
if (WIN1252_SWEDISH_BYTES.has(byte)) {
win1252Count++
}
// Check for UTF-8 multi-byte sequences for Swedish chars
// Ä = C3 84, Å = C3 85, Ö = C3 96, ä = C3 A4, å = C3 A5, ö = C3 B6
if (byte === 0xc3 && i + 1 < sampleSize) {
const nextByte = bytes[i + 1]
if ([0x84, 0x85, 0x96, 0xa4, 0xa5, 0xb6].includes(nextByte)) {
utf8Count++
i++ // Skip continuation byte to avoid false CP437 count (e.g. 0x84 = ä in CP437)
continue
}
}
}
if (utf8Count > cp437Count && utf8Count > win1252Count) return 'utf8'
if (cp437Count > win1252Count) return 'cp437'
if (win1252Count > 0) return 'windows1252'
return 'cp437'
}
/**
* Decode a buffer to string using the specified encoding
*/
export function decodeBuffer(buffer: ArrayBuffer, encoding: SIEEncoding): string {
if (encoding === 'utf8') {
const decoder = new TextDecoder('utf-8')
return decoder.decode(buffer)
}
if (encoding === 'windows1252') {
const decoder = new TextDecoder('windows-1252')
return decoder.decode(buffer)
}
// CP437 decoding
const bytes = new Uint8Array(buffer)
let result = ''
for (let i = 0; i < bytes.length; i++) {
const byte = bytes[i]
if (CP437_MAP[byte]) {
result += CP437_MAP[byte]
} else if (byte < 128) {
result += String.fromCharCode(byte)
} else {
// For other high bytes, try to preserve as-is
result += String.fromCharCode(byte)
}
}
return result
}
/**
* Parse a date from SIE format (YYYYMMDD)
*/
function parseSIEDate(dateStr: string): Date | null {
if (!dateStr || dateStr.length !== 8) {
return null
}
const year = parseInt(dateStr.substring(0, 4), 10)
const month = parseInt(dateStr.substring(4, 6), 10) - 1
const day = parseInt(dateStr.substring(6, 8), 10)
if (isNaN(year) || isNaN(month) || isNaN(day)) {
return null
}
const date = new Date(year, month, day)
// Reject invalid dates that auto-roll (e.g. Feb 30 → Mar 2)
if (date.getFullYear() !== year || date.getMonth() !== month || date.getDate() !== day) {
return null
}
return date
}
/**
* Parse a quoted string field from SIE
* Handles: "value" or value
*/
function parseStringField(field: string): string {
if (!field) return ''
// Remove surrounding quotes if present
if (field.startsWith('"') && field.endsWith('"')) {
return field.slice(1, -1).replace(/\\"/g, '"')
}
return field
}
/**
* Parse a numeric field from SIE
*/
function parseNumberField(field: string): number {
if (!field) return 0
// Strip quotes and use dot as decimal separator
const cleaned = parseStringField(field)
return parseFloat(cleaned.replace(',', '.')) || 0
}
/**
* Split a SIE line into fields, respecting quoted strings and braced object lists
*/
function splitSIELine(line: string): string[] {
const fields: string[] = []
let current = ''
let inQuotes = false
let braceDepth = 0
let escaped = false
for (let i = 0; i < line.length; i++) {
const char = line[i]
if (escaped) {
current += char
escaped = false
continue
}
if (char === '\\') {
escaped = true
current += char
continue
}
if (char === '"' && braceDepth === 0) {
inQuotes = !inQuotes
current += char
continue
}
// Track brace depth for object lists like {1 "ProjectA"}
if (char === '{' && !inQuotes) {
braceDepth++
current += char
continue
}
if (char === '}' && !inQuotes) {
braceDepth = Math.max(0, braceDepth - 1)
current += char
continue
}
if (char === ' ' && !inQuotes && braceDepth === 0) {
if (current) {
fields.push(current)
current = ''
}
continue
}
current += char
}
if (current) {
fields.push(current)
}
return fields
}
/**
* Add an issue to the issues list
*/
function addIssue(
issues: ParseIssue[],
severity: ParseIssueSeverity,
line: number,
message: string,
tag?: string
): void {
issues.push({ severity, line, message, tag })
}
/**
* Parse a SIE file content string
*/
export function parseSIEFile(content: string): ParsedSIEFile {
const lines = content.split(/\r?\n/)
const issues: ParseIssue[] = []
// Initialize header with defaults
const header: SIEHeader = {
sieType: 4,
program: null,
programVersion: null,
generatedDate: null,
format: null,
companyName: null,
orgNumber: null,
address: null,
fiscalYears: [],
currency: 'SEK',
kontoPlanType: null,
}
const accounts: SIEAccount[] = []
const openingBalances: SIEBalance[] = []
const closingBalances: SIEBalance[] = []
const resultBalances: SIEBalance[] = []
const vouchers: SIEVoucher[] = []
// Track current voucher being parsed (inside #VER { ... })
let currentVoucher: SIEVoucher | null = null
for (let i = 0; i < lines.length; i++) {
const lineNum = i + 1
const line = lines[i].trim()
// Skip empty lines
if (!line) continue
// Handle voucher block end
if (line === '}') {
if (currentVoucher) {
// Validate voucher balance
const total = currentVoucher.lines.reduce((sum, l) => sum + l.amount, 0)
if (Math.abs(total) > 0.01) {
addIssue(
issues,
'error',
lineNum,
`Voucher ${currentVoucher.series}${currentVoucher.number} is not balanced (diff: ${total.toFixed(2)})`,
'VER'
)
}
vouchers.push(currentVoucher)
currentVoucher = null
}
continue
}
// Handle voucher block start
if (line === '{') {
continue
}
// Skip lines that don't start with #
if (!line.startsWith('#')) {
continue
}
// Parse the tag and fields
const fields = splitSIELine(line)
const tag = fields[0].substring(1).toUpperCase()
try {
switch (tag) {
case 'FLAGGA':
// Flag for file handling - ignore
break
case 'FORMAT':
header.format = parseStringField(fields[1])
break
case 'SIETYP':
header.sieType = parseInt(fields[1], 10) as SIEType
if (![1, 2, 3, 4].includes(header.sieType)) {
addIssue(issues, 'warning', lineNum, `Unknown SIE type: ${fields[1]}`, tag)
header.sieType = 4
}
break
case 'PROGRAM':
header.program = parseStringField(fields[1])
header.programVersion = parseStringField(fields[2])
break
case 'GEN':
if (fields[1]) {
header.generatedDate = parseSIEDate(fields[1])
}
break
case 'ORGNR':
header.orgNumber = parseStringField(fields[1])
break
case 'FNAMN':
header.companyName = parseStringField(fields[1])
break
case 'ADRESS':
header.address = [fields[1], fields[2], fields[3], fields[4]]
.filter(Boolean)
.map(parseStringField)
.join(', ')
break
case 'VALUTA':
header.currency = parseStringField(fields[1]) || 'SEK'
break
case 'KPTYP':
header.kontoPlanType = parseStringField(fields[1])
break
case 'RAR': {
// #RAR yearIndex start end
const yearIndex = parseInt(fields[1], 10)
const start = parseSIEDate(fields[2])
const end = parseSIEDate(fields[3])
if (start && end) {
header.fiscalYears.push({ yearIndex, start, end })
} else {
addIssue(issues, 'warning', lineNum, 'Invalid fiscal year dates', tag)
}
break
}
case 'KONTO': {
// #KONTO number "name"
const number = fields[1]
const name = parseStringField(fields[2])
if (number && name) {
accounts.push({ number, name })
} else {
addIssue(issues, 'warning', lineNum, 'Invalid account definition', tag)
}
break
}
case 'SRU': {
// #SRU accountNumber sruCode
const accountNum = fields[1]
const sruCode = fields[2]
const account = accounts.find((a) => a.number === accountNum)
if (account) {
account.sruCode = sruCode
}
break
}
case 'KTYP': {
// #KTYP accountNumber type
const accountNum = fields[1]
const accountType = fields[2]
const account = accounts.find((a) => a.number === accountNum)
if (account) {
account.accountType = accountType
}
break
}
case 'IB': {
// #IB yearIndex accountNumber amount [quantity]
const yearIndex = parseInt(fields[1], 10)
const account = fields[2]
const amountStr = fields[3]
if (!amountStr || amountStr.trim() === '') {
addIssue(issues, 'warning', lineNum, 'Missing amount in #IB, skipping line', tag)
break
}
const amount = parseNumberField(amountStr)
const quantity = fields[4] ? parseNumberField(fields[4]) : undefined
if (account) {
openingBalances.push({ yearIndex, account, amount, quantity })
}
break
}
case 'UB': {
// #UB yearIndex accountNumber amount [quantity]
const yearIndex = parseInt(fields[1], 10)
const account = fields[2]
const amountStr = fields[3]
if (!amountStr || amountStr.trim() === '') {
addIssue(issues, 'warning', lineNum, 'Missing amount in #UB, skipping line', tag)
break
}
const amount = parseNumberField(amountStr)
const quantity = fields[4] ? parseNumberField(fields[4]) : undefined
if (account) {
closingBalances.push({ yearIndex, account, amount, quantity })
}
break
}
case 'RES': {
// #RES yearIndex accountNumber amount [quantity]
const yearIndex = parseInt(fields[1], 10)
const account = fields[2]
const amountStr = fields[3]
if (!amountStr || amountStr.trim() === '') {
addIssue(issues, 'warning', lineNum, 'Missing amount in #RES, skipping line', tag)
break
}
const amount = parseNumberField(amountStr)
const quantity = fields[4] ? parseNumberField(fields[4]) : undefined
if (account) {
resultBalances.push({ yearIndex, account, amount, quantity })
}
break
}
case 'VER': {
// #VER series number date "description" [regdate] [signature]
// Some programs quote all fields, so strip quotes from number/date too
const series = parseStringField(fields[1])
const number = parseInt(parseStringField(fields[2]), 10)
const date = parseSIEDate(parseStringField(fields[3]))
const description = parseStringField(fields[4])
if (!isNaN(number) && date) {
currentVoucher = {
series,
number,
date,
description: description || '',
lines: [],
}
// Optional registration date and signature
if (fields[5]) {
currentVoucher.registrationDate = parseSIEDate(parseStringField(fields[5])) || undefined
}
if (fields[6]) {
currentVoucher.signature = parseStringField(fields[6])
}
} else {
addIssue(issues, 'error', lineNum, 'Invalid voucher definition', tag)
}
break
}
case 'TRANS':
case 'RTRANS':
case 'BTRANS': {
// #TRANS = final transaction lines (the current state of the voucher)
// #RTRANS = removed lines (correction audit trail — original lines that were undone)
// #BTRANS = added lines (correction audit trail — new lines that replaced removed ones)
//
// When a voucher has been corrected, Fortnox/Visma emit all three types.
// Only #TRANS represents the final voucher state; #RTRANS and #BTRANS are
// supplementary history. We skip RTRANS/BTRANS to avoid double-counting
// which would make balanced vouchers appear unbalanced.
if (!currentVoucher) {
addIssue(issues, 'error', lineNum, `${tag} outside of VER block`, tag)
break
}
// Skip RTRANS/BTRANS — they are correction audit trail, not final state
if (tag === 'RTRANS' || tag === 'BTRANS') {
break
}
// Parse account and skip object list (in braces)
let fieldIndex = 1
const account = parseStringField(fields[fieldIndex++])
// Skip object list if present (now a single field thanks to brace-aware splitting)
if (fields[fieldIndex]?.startsWith('{')) {
fieldIndex++
}
const transAmountStr = fields[fieldIndex]
if (!transAmountStr || transAmountStr.trim() === '') {
addIssue(issues, 'warning', lineNum, `Missing amount in #${tag}, skipping line`, tag)
break
}
const amount = parseNumberField(fields[fieldIndex++])
const transLine: SIETransactionLine = {
account,
amount,
}
// Optional fields
if (fields[fieldIndex]) {
transLine.date = parseSIEDate(parseStringField(fields[fieldIndex++])) || undefined
}
if (fields[fieldIndex]) {
transLine.description = parseStringField(fields[fieldIndex++])
}
if (fields[fieldIndex]) {
transLine.quantity = parseNumberField(fields[fieldIndex++])
}
if (fields[fieldIndex]) {
transLine.signature = parseStringField(fields[fieldIndex++])
}
currentVoucher.lines.push(transLine)
break
}
default:
// Unknown tag - add info issue for notable ones
if (!['KSUMMA', 'BKOD', 'TAXAR', 'OMFATTN', 'DIM', 'OBJEKT', 'OIB', 'OUB', 'PBUDGET', 'PSALDO'].includes(tag)) {
addIssue(issues, 'info', lineNum, `Unknown tag: #${tag}`, tag)
}
}
} catch (error) {
addIssue(
issues,
'error',
lineNum,
`Error parsing ${tag}: ${error instanceof Error ? error.message : 'Unknown error'}`,
tag
)
}
}
// Collect accounts referenced in balances and vouchers but missing from #KONTO
const definedAccountNumbers = new Set(accounts.map((a) => a.number))
const referencedAccounts = new Set<string>()
for (const balance of [...openingBalances, ...closingBalances, ...resultBalances]) {
if (balance.account && !definedAccountNumbers.has(balance.account)) {
referencedAccounts.add(balance.account)
}
}
for (const voucher of vouchers) {
for (const line of voucher.lines) {
if (line.account && !definedAccountNumbers.has(line.account)) {
referencedAccounts.add(line.account)
}
}
}
for (const accountNumber of referencedAccounts) {
accounts.push({ number: accountNumber, name: '' })
addIssue(issues, 'info', 0, `Account ${accountNumber} added from transaction data (not in #KONTO)`)
}
// Calculate statistics
const currentFiscalYear = header.fiscalYears.find((fy) => fy.yearIndex === 0)
const totalTransactionLines = vouchers.reduce((sum, v) => sum + v.lines.length, 0)
return {
header,
accounts,
openingBalances,
closingBalances,
resultBalances,
vouchers,
issues,
stats: {
totalAccounts: accounts.length,
totalVouchers: vouchers.length,
totalTransactionLines,
fiscalYearStart: currentFiscalYear?.start || null,
fiscalYearEnd: currentFiscalYear?.end || null,
},
}
}
/**
* Validate a parsed SIE file
*/
export function validateSIEFile(parsed: ParsedSIEFile): ValidationResult {
const errors: string[] = []
const warnings: string[] = []
// Check for SIE type
if (!parsed.header.sieType) {
errors.push('Missing SIE type (#SIETYP)')
}
// Check for company info
if (!parsed.header.companyName) {
warnings.push('No company name found (#FNAMN)')
}
// Check for fiscal year
if (parsed.header.fiscalYears.length === 0) {
errors.push('No fiscal year defined (#RAR)')
}
// Check for accounts
if (parsed.accounts.length === 0) {
warnings.push('No accounts found (#KONTO)')
}
// Warn if non-BAS kontoplan declared — mapping logic assumes BAS number ranges
if (parsed.header.kontoPlanType) {
const planType = parsed.header.kontoPlanType.toUpperCase()
const isBAS = planType.startsWith('BAS') || planType === 'EUBAS' || planType === 'EU-BAS'
if (!isBAS) {
warnings.push(
`Kontoplanstyp "${parsed.header.kontoPlanType}" är inte BAS-baserad. Alla kontomappningar bör granskas manuellt.`
)
}
}
// Check for unbalanced vouchers
for (const voucher of parsed.vouchers) {
const total = voucher.lines.reduce((sum, l) => sum + l.amount, 0)
if (Math.abs(total) > 0.01) {
errors.push(
`Voucher ${voucher.series}${voucher.number} on ${voucher.date.toISOString().split('T')[0]} is not balanced (diff: ${total.toFixed(2)})`
)
}
}
// Check for accounts referenced but not defined
const definedAccounts = new Set(parsed.accounts.map((a) => a.number))
const referencedAccounts = new Set<string>()
for (const balance of [...parsed.openingBalances, ...parsed.closingBalances, ...parsed.resultBalances]) {
referencedAccounts.add(balance.account)
}
for (const voucher of parsed.vouchers) {
for (const line of voucher.lines) {
referencedAccounts.add(line.account)
}
}
for (const account of referencedAccounts) {
if (!definedAccounts.has(account)) {
warnings.push(`Account ${account} referenced but not defined in #KONTO`)
}
}
// Check opening balance is balanced (for balance sheet accounts)
const ibTotal = parsed.openingBalances
.filter((b) => b.yearIndex === 0)
.reduce((sum, b) => sum + b.amount, 0)
if (Math.abs(ibTotal) > 0.01) {
warnings.push(`Opening balances not balanced (diff: ${ibTotal.toFixed(2)})`)
}
// Add parse issues as errors/warnings
for (const issue of parsed.issues) {
if (issue.severity === 'error') {
errors.push(`Line ${issue.line}: ${issue.message}`)
} else if (issue.severity === 'warning') {
warnings.push(`Line ${issue.line}: ${issue.message}`)
}
}
return {
valid: errors.length === 0,
errors,
warnings,
}
}
/**
* Calculate a hash of the file content for duplicate detection
*/
export async function calculateFileHash(content: string): Promise<string> {
const encoder = new TextEncoder()
const data = encoder.encode(content)
const hashBuffer = await crypto.subtle.digest('SHA-256', data)
const hashArray = Array.from(new Uint8Array(hashBuffer))
return hashArray.map((b) => b.toString(16).padStart(2, '0')).join('')
}