@middy/http-event-normalizer/index.js

const httpEventNormalizerMiddleware = ()=>{
    const httpEventNormalizerMiddlewareBefore = async (request)=>{
        const { event } = request;
        const version = pickVersion(event);
        // VPC Lattice is an http event, however uses a different notation
        // - query_string_parameters
        // - is_base64_encoded
        if (version === '1.0') {
            event.multiValueQueryStringParameters ??= {};
        } else if (version === 'vpc') {
            event.queryStringParameters = event.query_string_parameters;
            event.isBase64Encoded = event.is_base64_encoded;
        }
        // event.headers ??= {} // Will always have at least one header
        event.pathParameters ??= {};
        event.queryStringParameters ??= {};
    };
    return {
        before: httpEventNormalizerMiddlewareBefore
    };
};
const pickVersion = (event)=>{
    // '1.0' is a safer default
    return event.version ?? (event.method ? 'vpc' : '1.0');
};
export default httpEventNormalizerMiddleware;