alanchauchet / dynamo-stream-record-parser

A simple and fast parser of AWS Dynamo stream records

Dynamo StreamRecord parser

dynamo-stream-record-parser is a simple function that helps you parse an AWS Dynamo StreamRecord

Installation

Dynamo StreamRecord parser is available as dynamo-stream-record-parser package on npm

With npm

$ npm install dynamo-stream-record-parser --save

If using yarn

$ yarn add dynamo-stream-record-parser

Examples

dynamo-stream-record-parser exports a parseDynamoStreamRecord function which parses the data you'll pass as first parameter and returns the parsed value
You can use parseDynamoStreamRecord with any type of value but it will only parse it if it is an array or an object (in any other case, it will just return the given parameter unchanged):

Use with a Dynamo StreamRecord

import { parseDynamoStreamRecord } from 'dynamo-stream-record-parser';

const streamRecord = {
     eventID: "8f9e7f8e6fg876f78sdf7d9sdf",
     eventName: "INSERT",
     eventVersion: "1.1",
     eventSource: "aws:dynamodb",
     awsRegion: "us-west-2",
     dynamodb: {
       Keys: {
         Id: {
           N: "101"
         }
       },
       NewImage: {
         Message: {
           S: "New item!"
         },
         Id: {
           N: "101"
         }
       },
       ApproximateCreationDateTime: 1428537600,
       SequenceNumber: "1234567890",
       SizeBytes: 26,
       StreamViewType: "NEW_AND_OLD_IMAGES"
     },
     eventSourceARN: "arn:aws:blahblahblah"
}

const parsedStreamRecord = parseDynamoStreamRecord(streamRecord);

// parsedStreamRecord.dynamodb =
// {
//   Keys: {
//     Id: 101
//   },
//   NewImage: {
//     Message: "New item!",
//     Id: 101
//   }
// }
// (Note that other keys of base streamRecord are left unchanged in parsedStreamRecord)

Use with an array of Dynamo StreamRecord

import { parseDynamoStreamRecord } from 'dynamo-stream-record-parser';

const streamRecords = [{
  Keys: {
    Id: {
      N: "101"
    }
  }
}, {
  NewImage: {
    Message: {
      S: "New item!"
    },
    Id: {
      N: "101"
    }
  }
}];

const parsedStreamRecords = parseDynamoStreamRecord(streamRecords);

// parsedStreamRecords =
// [{
//   Keys: {
//     Id: 101
//   }
//  }, {
//   NewImage: {
//     Message: "New item!",
//     Id: 101
//   }
// }]
//

Use with large numbers

The Dynamo StreamRecords holds number values as string because it can go up to 9.9999999999999999999999999999999999999E+125. By default, the parser will convert those strings into numbers which could lead to a loss of precision. If you want to avoid that, you can pass true as the second parameter of parseDynamoStreamRecord and then all StreamRecords numbers will be converted to BigInt instead of regular Number.