Function to scan AWS Dynamo DB recursively for Nodejs - node.js

Question

So I need a recursive function in node.js for replacing this function call:
docClient.scan(params, callback)
More info see http://docs.aws.amazon.com/amazondynamodb/latest/gettingstartedguide/GettingStarted.NodeJs.04.html

Answer 1

Here is the recursive code to execute the scan until LastEvaluatedKey is available.
var AWS = require("aws-sdk");
var creds = new AWS.Credentials('akid', 'secret', 'session');
AWS.config.update({
region: "us-west-2",
endpoint: "http://localhost:8000",
credentials : creds
});
var docClient = new AWS.DynamoDB.DocumentClient();
var params = {
TableName: "Movies"
};
console.log("Scanning Movies table.");
docClient.scan(params, onScan);
var count = 0;
function onScan(err, data) {
if (err) {
console.error("Unable to scan the table. Error JSON:", JSON.stringify(err, null, 2));
} else {
// print all the movies
console.log("Scan succeeded.");
data.Items.forEach(function(movie) {
console.log("Item :", ++count,JSON.stringify(movie));
});
// continue scanning if we have more movies
if (typeof data.LastEvaluatedKey != "undefined") {
console.log("Scanning for more...");
params.ExclusiveStartKey = data.LastEvaluatedKey;
docClient.scan(params, onScan);
}
}
}

Answer 2

Recursive DynamoDB Scan using AWS SDK V3.
import {
DynamoDBClient,
ScanCommand,
ScanCommandOutput,
ScanCommandInput,
} from '#aws-sdk/client-dynamodb';
import { unmarshall, marshall } from '#aws-sdk/util-dynamodb';
const client = new DynamoDBClient({ region: 'eu-west-1' });
export const scanTable = async<ResultType>(params: ScanCommandInput): Promise<ResultType[]> => {
const scanParams: ScanCommandInput = params;
const results = [];
let lastEvaluatedKey: string;
do {
console.log(`Running query: ${JSON.stringify(scanParams)}`);
const { Items, LastEvaluatedKey } = await client.send(new ScanCommand(scanParams));
lastEvaluatedKey = LastEvaluatedKey;
Items.forEach((item) => results.push(unmarshall(item)));
scanParams.ExclusiveStartKey = LastEvaluatedKey;
} while (typeof lastEvaluatedKey !== 'undefined');
return results as ResultType[];
};
const items = await scanTable({ TableName: 'dynamo-table' })