AWS Lambda function to class Cloud Search API with javascript SDK

docSearcher_snippet1.js

exports.handler = (event, context, callback) => {
  
    var csd = new AWS.CloudSearchDomain({
        endpoint: CS_NAME+'.'+SERVICES_REGION+'.cloudsearch.amazonaws.com',
        apiVersion: '2013-01-01'
    });
  
    var params = {
        query: event.query,
        sort: '_score desc',
        size: event.size, // number of documents to return
        start: event.start, // start index of document list to return (cf multi tab)
        queryOptions: JSON.stringify({fields: ['content']}),
    };
    // see documentation at :
    // docs.aws.amazon.com/AWSJavaScriptSDK/latest/AWS/CloudSearchDomain.html#search-property
    csd.search(params, function(err, data) {
        if (err) {
            callback('CloudSearch ERROR');
            context.done();
        }
        else {
            callback(null, data); // SUCCESS
            context.done();
        }
    });
};