index.js

// dependencies
const AWS = require('aws-sdk');
const util = require('util');
// const attr = require('dynamodb-data-types').AttributeValue;


// get reference to S3 client
const s3 = new AWS.S3();

// Set the AWS Region
 const REGION = "ca-central-1"; //e.g. "us-east-1"
 const dbclient = new AWS.DynamoDB.DocumentClient({ region: REGION });
 
 
 // JSON - Insert to Dynamo Table
const insertToDynamoTable = async function(json){
    try{
        let dynamoTableName = 'sample-table'
        let dynamoDBRecords = getDynamoDBRecords(json)
        let batches = [];

        while(dynamoDBRecords.length) {
            batches.push(dynamoDBRecords.splice(0, 25));
        }
        
        await Promise.all(
            batches.map(async (batch) =>{
                    let requestItems = {}
                    requestItems[dynamoTableName] = batch
                    const params = {
                        RequestItems: requestItems
                    };
                    
                    console.log(params)
                    await dbclient.batchWrite(params).promise()
                })
        );
        
    } catch (error) {
        console.log(error);
        return error;
    }
}

// Get DynamoDB records from json
const getDynamoDBRecords = function (data) {
    let dynamoDBRecords = data.Sheet1.map(entity => {
        console.log(entity)
        let dynamoRecord = Object.assign({ PutRequest: { Item: entity } })
        return dynamoRecord
    })

    return dynamoDBRecords
}


exports.handler = async (event, context) => {   
    // Read options from the event parameter.
    console.log("Reading options from event:\n", util.inspect(event, { depth: 5 }));
    const srcBucket = event.Records[0].s3.bucket.name;

    // Object key may have spaces or unicode non-ASCII characters.
    const srcKey = decodeURIComponent(event.Records[0].s3.object.key.replace(/\+/g, " "));

    let json_data = {}
    let response = {}
    
    try {
        const params = {
            Bucket: srcBucket,
            Key: srcKey
        };
        
        response = await s3.getObject(params).promise();

    } catch (error) {
        console.log(error);
        return;
    }
    
    json_data = response.Body.toString('utf-8')
    json_data = JSON.parse(json_data)
   
    const data = await  insertToDynamoTable(json_data)     
    return `Successfully processed ${json_data.Sheet1.length} records.`;
};