Create the browser script - AWS SDK for JavaScript

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The AWS SDK for JavaScript V3 API Reference Guide describes in detail all the API operations for the AWS SDK for JavaScript version 3 (V3).

Create the browser script

Configuring the SDK

Create a libs directory, and create a Node.js module with the file name kinesisClient.js. Copy and paste the code below into it, which creates the Kinesis client object. Replace REGION with your AWS Region. Replace IDENTITY_POOL_ID with the Amazon Cognito identity pool id you created in Create the AWS resources .

// Import the required AWS SDK clients and commands for Node.js. const {CognitoIdentityClient} = require("@aws-sdk/client-cognito-identity"); const { fromCognitoIdentityPool, } = require("@aws-sdk/credential-provider-cognito-identity"); const { KinesisClient, PutRecordsCommand } = require("@aws-sdk/client-kinesis"); // Configure Credentials to use Cognito const REGION = "REGION"; const kinesisClient = new KinesisClient({ region: REGION, credentials: fromCognitoIdentityPool({ client: new CognitoIdentityClient({region: REGION}), identityPoolId: "IDENTITY_POOL_ID" // IDENTITY_POOL_ID }) }); export {kinesisClient}

You can find this code here on GitHub.

Creating Scroll Records

Scroll progress is calculated using the scrollHeight and scrollTop properties of the <div> containing the content of the blog post. Each scroll record is created in an event listener function for the scroll event and then added to an array of records for periodic submission to Kinesis. Replace PARTITION_KEY with a paritition key, which must be a string. For more information about partition strings, see PutRecord in the Amazon Kinesis Data Analytics developer guide.

The following code snippet shows this step. (See Bundling the browser script for the full example.)

import { PutRecordsCommand } from "@aws-sdk/client-kinesis"; import { kinesisClient } from "./libs/kinesisClient.js"; // Get the ID of the web page element. var blogContent = document.getElementById('BlogContent'); // Get scrollable height. var scrollableHeight = blogContent.clientHeight; var recordData = []; var TID = null; blogContent.addEventListener('scroll', function(event) { console.log('scrolled'); clearTimeout(TID); // Prevent creating a record while a user is actively scrolling. TID = setTimeout(function() { // Calculate the percentage. var scrollableElement =; var scrollHeight = scrollableElement.scrollHeight; var scrollTop = scrollableElement.scrollTop; var scrollTopPercentage = Math.round((scrollTop / scrollHeight) * 100); var scrollBottomPercentage = Math.round(((scrollTop + scrollableHeight) / scrollHeight) * 100); // Create the Amazon Kinesis record. var record = { Data: JSON.stringify({ blog: window.location.href, scrollTopPercentage: scrollTopPercentage, scrollBottomPercentage: scrollBottomPercentage, time: new Date() }), PartitionKey: 'PARTITION_KEY' // Must be a string. }; recordData.push(record); }, 100); });

Submitting Records to Kinesis

Once each second, if there are records in the array, those pending records are sent to Kinesis. Replace STREAM_NAME with the name of the stream you created in the Create the AWS resources section of this example.


This example imports and uses the required AWS Service V3 package clients, V3 commands, and uses the send method in an async/await pattern. You can create this example using V2 commands instead by making some minor changes. For details, see Using V3 commands.

The following code snippet shows this step. (See Bundling the browser script for the full example.)

// Helper function to upload data to Amazon Kinesis. const uploadData = async () => { try { const data = await client.send(new PutRecordsCommand({ Records: recordData, StreamName: 'STREAM_NAME' })); console.log('data', data); console.log("Kinesis updated", data); } catch (err) { console.log("Error", err); } }; // Run uploadData every second if data exists. setInterval(function() { if (!recordData.length) { return; } uploadData(); // clear record data recordData = []; }, 1000);