lib/util.js

119 lines4,282 bytessha256 06aa6d68b04f

// LEASH wallet-control — shared utilities (zero-dependency).
import fs from 'node:fs';
/** Minimal RFC-4180 CSV parser (handles quoted fields, embedded commas/newlines). */
export function parseCsv(text) {
const rows = [];
let row = [], field = '', inQ = false, i = 0;
if (text.charCodeAt(0) === 0xfeff) i = 1; // BOM
while (i < text.length) {
const c = text[i];
if (inQ) {
if (c === '"') {
if (text[i + 1] === '"') { field += '"'; i += 2; continue; }
inQ = false; i++; continue;
}
field += c; i++; continue;
}
if (c === '"') { inQ = true; i++; continue; }
if (c === ',') { row.push(field); field = ''; i++; continue; }
if (c === '\r') { i++; continue; }
if (c === '\n') { row.push(field); rows.push(row); row = []; field = ''; i++; continue; }
field += c; i++;
}
if (field.length || row.length) { row.push(field); rows.push(row); }
if (!rows.length) return [];
const header = rows[0].map(h => h.trim());
return rows.slice(1).filter(r => r.length > 1 || r[0] !== '')
.map(r => Object.fromEntries(header.map((h, idx) => [h, r[idx] ?? ''])));
}
export function loadCsv(path) {
return parseCsv(fs.readFileSync(path, 'utf8'));
}
export const round2 = (n) => Math.round(n * 100) / 100;
/** Convert an amount between pack currencies using the fixed synthetic rates. */
export const FX = { CHF: 1.0, EUR: 0.95, GBP: 1.12, USD: 0.87 }; // to CHF, rate_date 2026-08-01
export function toChf(amount, currency) {
const rate = FX[(currency || 'CHF').toUpperCase()];
// The pack uses decimal half-even rounding, including negative refunds.
// Rates have two decimals; integer arithmetic avoids binary half-cent drift.
const scaled = Math.round(Number(amount) * 100) * Math.round((rate ?? 1) * 100);
if (!Number.isSafeInteger(scaled)) return NaN;
const magnitude = Math.abs(scaled);
const cents = Math.floor(magnitude / 100);
const remainder = magnitude % 100;
const rounded = cents + (remainder > 50 || (remainder === 50 && cents % 2 !== 0) ? 1 : 0);
return Math.sign(scaled) * rounded / 100;
}
export function num(v) {
if (v === null || v === undefined || v === '') return null;
const n = Number(v);
return Number.isFinite(n) ? n : null;
}
/** null-preserving string: '' -> null */
export function str(v) {
if (v === null || v === undefined || v === '') return null;
return String(v);
}
export function parseTs(s) {
return s ? new Date(s).getTime() : null;
}
export function fmtChf(n) {
return `CHF ${round2(n).toFixed(2)}`;
}
/** Normalize a merchant/item name for comparison: lowercase, letters+digits only. */
export function normalizeName(s) {
return String(s || '').toLowerCase().replace(/[^a-z0-9]+/g, '');
}
/** Jaro-Winkler similarity in [0,1] — used for lookalike-merchant detection. */
export function jaroWinkler(a, b) {
const s1 = normalizeName(a), s2 = normalizeName(b);
if (!s1.length || !s2.length) return 0;
if (s1 === s2) return 1;
const window = Math.max(0, Math.floor(Math.max(s1.length, s2.length) / 2) - 1);
const f1 = new Array(s1.length).fill(false), f2 = new Array(s2.length).fill(false);
let m = 0;
for (let i = 0; i < s1.length; i++) {
const lo = Math.max(0, i - window), hi = Math.min(s2.length - 1, i + window);
for (let j = lo; j <= hi; j++) {
if (!f2[j] && s1[i] === s2[j]) { f1[i] = true; f2[j] = true; m++; break; }
}
}
if (!m) return 0;
let k = 0, t = 0;
for (let i = 0; i < s1.length; i++) {
if (f1[i]) {
while (!f2[k]) k++;
if (s1[i] !== s2[k]) t++;
k++;
}
}
const jaro = (m / s1.length + m / s2.length + (m - t / 2) / m) / 3;
let p = 0;
const maxPrefix = Math.min(4, s1.length, s2.length);
while (p < maxPrefix && s1[p] === s2[p]) p++;
return jaro + p * 0.1 * (1 - jaro);
}
export function escapeHtml(s) {
return String(s ?? '').replace(/[&<>"']/g, c => ({ '&': '&', '<': '<', '>': '>', '"': '"', "'": ''' }[c]));
}
/** Truncate long untrusted text for evidence display. */
export function clip(s, n = 90) {
s = String(s ?? '');
return s.length <= n ? s : s.slice(0, n - 1) + '…';
}
export function readJsonIfExists(path) {
try { return JSON.parse(fs.readFileSync(path, 'utf8')); } catch { return null; }
}