Route requests to an origin closer to the viewer in a CloudFront Functions viewer request event

import cf from 'cloudfront';

function handler(event) {
    const request = event.request;
    const headers = request.headers;
    const country = headers['cloudfront-viewer-country'] &&
        headers['cloudfront-viewer-country'].value;

    //List of Regions with S3 buckets containing content
    const countryToRegion = {
        'DE': 'eu-central-1',
        'IE': 'eu-west-1',
        'GB': 'eu-west-2',
        'FR': 'eu-west-3',
        'JP': 'ap-northeast-1',
        'IN': 'ap-south-1'
    };

    const DEFAULT_REGION = 'us-east-1';

    const selectedRegion = (country && countryToRegion[country]) || DEFAULT_REGION;

    const domainName =
        `cloudfront-functions-demo-bucket-in-${selectedRegion}.s3.${selectedRegion}.amazonaws.com`;

    cf.updateRequestOrigin({
        "domainName": domainName,
        "originAccessControlConfig": {
            "enabled": true,
            "region": selectedRegion,
            "signingBehavior": "always",
            "signingProtocol": "sigv4",
            "originType": "s3"
        },
    });

    return request;
}