Aggregate multiple CSV files from brokerage accounts

aggregateBrokerageCSVs.js

const fs = require('fs');const csv = require('csv-parser');
const createCsvWriter = require('csv-writer').createObjectCsvWriter;
const { argv } = require('process');

async function processCSV(filePath) {
    const results = [];
    return new Promise((resolve, reject) => {
        fs.createReadStream(filePath) // Correct usage of createReadStream
            .pipe(csv())
            .on('data', (data) => {
                try {
                    const { Symbol, Quantity, 'Cost Basis Total': costBasisTotal } = data;
                    if (Symbol && Quantity && costBasisTotal) {
                        results.push({
                            Symbol: Symbol.trim(),
                            Quantity: parseFloat(Quantity.replace(/,/g, '')),
                            'Cost Basis Total': parseFloat(costBasisTotal.replace(/[$,]/g, '')), // Remove $ and ,
                        });
                    }
                } catch (error) {
                    console.error(`Error processing row in ${filePath}:`, data, error);
                }
            })
            .on('end', () => resolve(results))
            .on('error', reject);
    });
}


async function aggregateData(filePaths) {
    const aggregatedData = {};

    for (const filePath of filePaths) {
        try {
            const data = await processCSV(filePath);
            for (const item of data) {
                if (!aggregatedData[item.Symbol]) {
                    aggregatedData[item.Symbol] = { ...item };
                } else {
                    aggregatedData[item.Symbol].Quantity += item.Quantity;
                    aggregatedData[item.Symbol]['Cost Basis Total'] += item['Cost Basis Total'];
                }
            }
        } catch (error) {
            console.error(`Error processing file ${filePath}:`, error);
        }
    }

    return Object.values(aggregatedData);
}

async function writeToCSV(data, outputPath) {
    if (data.length === 0) {
        console.log("No data to write to CSV.");
        return;
    }
    
    // Sort the data alphabetically by Symbol
    data.sort((a, b) => {
        const symbolA = a.Symbol.toUpperCase(); // Ignore case during sorting
        const symbolB = b.Symbol.toUpperCase();
        if (symbolA < symbolB) {
            return -1;
        }
        if (symbolA > symbolB) {
            return 1;
        }
        return 0; // symbols are equal
        });
    
    const csvWriter = createCsvWriter({
        path: outputPath,
        header: [
            { id: 'Symbol', title: 'Symbol' },
            { id: 'Quantity', title: 'Quantity' },
            { id: 'Cost Basis Total', title: 'Cost Basis Total' },
        ],
    });

    try {
        await csvWriter.writeRecords(data);
        console.log(`Data written to ${outputPath}`);
    } catch (err) {
        console.error('Error writing CSV:', err);
    }
}

async function main() {
    const inputFiles = argv.slice(2); // Get file paths from command line arguments
    const outputFile = 'aggregated_holdings.csv';

    if (inputFiles.length === 0) {
        console.error('Please provide input file paths as command line arguments.');
        process.exit(1);
    }

    const aggregated = await aggregateData(inputFiles);
    await writeToCSV(aggregated, outputFile);
}

main();