AWS Excel Read + Update DB Lambda

excel-lambda.js

const AWS = require('aws-sdk')
AWS.config.update({
    region: "<region>",
});
const s3 = new AWS.S3()
const docClient = new AWS.DynamoDB.DocumentClient();
const xlsx = require('node-xlsx')
const testfilename = "<file>.xlsm"

// src: https://stackoverflow.com/questions/40535757/download-xlsx-from-s3-and-parse-it
exports.handler = (event, context, callback) => {
    const params = {
        Bucket: "<bucket>",
        Key: testfilename
    };
    let buffers = [];
    const stream = s3.getObject(params).createReadStream();

    stream.on('data', function (data) {
        buffers.push(data);
    });

    stream.on('end', function () {
        const buffer = Buffer.concat(buffers);
        const workbook = xlsx.parse(buffer);
        const [header, ...dataRows] = workbook[0].data
        dataRows.forEach((row, i) => {
            populateDB(row)
        })
        context.succeed('done')
    });

    stream.on('error', (err) => {
        console.error(`--- ERROR ---`)
        console.error(err)
    });
}

const populateDB = row => {
    const TableName = '<table name>'
    const Item = {
        a: row[0],
        b: row[4],
        c: row[5],
        d: row[8],
        e: row[7],
        f: row[15]
    }

    const dbparams = {
        TableName,
        Item
    }

    docClient.put(dbparams, function (err, data) {
        if (err) {
            console.error("Unable to add item. Error JSON:", JSON.stringify(err, null, 2));
        } else {
            console.log("Added item:", JSON.stringify(data, null, 2));
        }
    });
}

great