@baruchiro/actual-mcp/build/tools/balance-history/balance-calculator.js

Actual Budget MCP server exposing API functionality

export class BalanceHistoryCalculator {
    calculate(transactions, currentBalance, months, endDate) {
        const balanceHistory = {};
        let runningBalance = currentBalance;
        // Sort transactions by date (newest first)
        const sortedTransactions = [...transactions].sort((a, b) => {
            return new Date(b.date).getTime() - new Date(a.date).getTime();
        });
        // Initialize with current balance for current month
        const currentYearMonth = `${endDate.getFullYear()}-${String(endDate.getMonth() + 1).padStart(2, "0")}`;
        balanceHistory[currentYearMonth] = {
            year: endDate.getFullYear(),
            month: endDate.getMonth() + 1,
            balance: runningBalance,
            transactions: 0,
        };
        // Process transactions to calculate past balances
        sortedTransactions.forEach((transaction) => {
            const date = new Date(transaction.date);
            const yearMonth = `${date.getFullYear()}-${String(date.getMonth() + 1).padStart(2, "0")}`;
            // Subtract transaction amount from running balance (going backwards in time)
            runningBalance -= transaction.amount;
            if (!balanceHistory[yearMonth]) {
                balanceHistory[yearMonth] = {
                    year: date.getFullYear(),
                    month: date.getMonth() + 1,
                    balance: runningBalance,
                    transactions: 0,
                };
            }
            balanceHistory[yearMonth].transactions += 1;
        });
        // Convert to array and sort by date
        let sortedMonths = Object.values(balanceHistory).sort((a, b) => {
            if (a.year !== b.year)
                return a.year - b.year;
            return a.month - b.month;
        });
        // Only include the most recent N months
        if (sortedMonths.length > months) {
            sortedMonths = sortedMonths.slice(sortedMonths.length - months);
        }
        return sortedMonths;
    }
}