AWS: Lambda function to transfer any URL to S3 v2

import * as fs from 'fs';
import * as https from 'https'
import { S3Client, PutObjectCommand } from "@aws-sdk/client-s3";

export const handler = async(event) => {

    // get url from querystring in the event
    const url = event.queryStringParameters.url;
    // extract file name from url
    const fileName = url.substring(url.lastIndexOf('/') + 1);
    await transferFile(url, '/tmp/' + fileName);
    return {
        statusCode: 200,
        body: JSON.stringify('ok'),
    };
};

function uploadFileToS3(filePath, bucketName) {
    const s3Client = new S3Client({ region: 'us-east-1' });
    const command = new PutObjectCommand({
        Bucket: bucketName,
        Key: filePath,
        Body: fs.readFileSync(filePath),
    });
    return s3Client.send(command);
}

// function for downloading a file from an url to disk and resolve on closes
function downloadFile(url, file) {
    return new Promise((resolve, reject) => {
        const fileStream = fs.createWriteStream(file);
        https.get(url, (response) => {
            response.pipe(fileStream);
            fileStream.on('close', () => {
                resolve();
            });
        }).on('error', (err) => {
            reject(err);
        });
    });
}

// async function for transferring a file from an url to a bucket
async function transferFile(url, filePath) {
    await downloadFile(url, filePath);
    await uploadFileToS3(filePath, 'demo-lambda-codewhisperer');
}