Check index whether exist or not then if not yet exist, create Index and Save document.

index.js

const elasticsearch = require('elasticsearch');
const esClient = new elasticsearch.Client({
    host: process.env.ES_ENDPOINT,
    apiVersion: "7.1",
});

exports.handler = async (event, context, callback) => {
    const indexName = 'notifications';
    const id = event.input.id;
    const documents = event.input;
    delete documents.id;
    
    let checkIndex = await checkESIndices(indexName);
	if (!checkIndex) {
		return await createESIndex(indexName).then(async () => {
			return await addESDocument(indexName, 'logs', id, documents);
		});
	} else {
		return await addESDocument(indexName, 'logs', id, documents);
	}
};


const checkESIndices = async (indexName) => {
	return await esClient.indices.exists({ index: indexName });
};

const createESIndex = async (indexName) => {
	return await esClient.indices.create({ index: indexName });
};

const addESDocument = async (indexName, indexType, id, indexDocuments) => {
	return await esClient.index({
		index: indexName,
		type: indexType,
		id: id,
		body: indexDocuments
	}).then(() => {
		const response = {
			statusCode: 200,
			body: {
				title: indexDocuments.title,
				username: indexDocuments.username
			}
		};
		console.log(JSON.stringify(response));
		return response;
	});
};