# @elastic/elasticsearch
[](http://standardjs.com/) [](https://clients-ci.elastic.co/job/elastic+elasticsearch-js+master/) [](https://codecov.io/gh/elastic/elasticsearch-js) [](https://www.npmjs.com/package/@elastic/elasticsearch)
---
**Note:** In the past months we have worked on the new Elasticsearch Node.js client, and if you want you can already try it by following the instructions below, while if you're going to use the legacy one or report an issue, please check out [elastic/elasticsearch-js-legacy](https://github.com/elastic/elasticsearch-js-legacy).
---
The official Node.js client for Elasticsearch.
## Features
- One-to-one mapping with REST API.
- Generalized, pluggable architecture.
- Configurable, automatic discovery of cluster nodes.
- Persistent, Keep-Alive connections.
- Load balancing (with pluggable selection strategy) across all available nodes.
- TypeScript support out of the box.
## Install
```
npm install @elastic/elasticsearch
```
### Compatibility
The minimum supported version of Node.js is `v8`.
The library is compatible with all Elasticsearch versions since 5.x, but you should use the same major version of the Elasticsearch instance that you are using.
```
# Elasticsearch 7.x
@elastic/elasticsearch@7
# Elasticsearch 6.x
@elastic/elasticsearch@6
# Elasticsearch 5.x
@elastic/elasticsearch@5
```
#### Install multiple versions
If you are using multiple versions of Elasticsearch, you need to use multiple versions of the client. In the past, install multiple versions of the same package was not possible, but with `npm v6.9`, you can do that via aliasing.
The command you must run to install different version of the client is:
```sh
npm install @npm:@elastic/elasticsearch@
```
So for example if you need to install `7.x` and `6.x`, you will run
```sh
npm install es6@npm:@elastic/elasticsearch@6
npm install es7@npm:@elastic/elasticsearch@7
```
And your `package.json` will look like the following:
```json
"dependencies": {
"es6": "npm:@elastic/elasticsearch@^6.7.0",
"es7": "npm:@elastic/elasticsearch@^7.0.0"
}
```
And finally, you will require the packages from your code by using the alias you have defined.
```js
const { Client: Client6 } = require('es6')
const { Client: Client7 } = require('es7')
const client6 = new Client6({ node: 'http://localhost:9200' })
const client7 = new Client7({ node: 'http://localhost:9201' })
client6.info(console.log)
client7.info(console.log)
```
Finally, if you want to install the client for the next version of Elasticsearch *(the one that lives in Elasticsearch’s master branch)*, you can use the following command:
```sh
npm install esmaster@github:elastic/elasticsearch-js
```
## Usage
You can find the full documentation in our [docs](https://www.elastic.co/guide/en/elasticsearch/client/javascript-api/current/index.html) website.
```js
const { Client } = require('@elastic/elasticsearch')
const client = new Client({ node: 'http://localhost:9200' })
// promise API
const result = await client.search({
index: 'my-index',
body: { foo: 'bar' }
})
// callback API
client.search({
index: 'my-index',
body: { foo: 'bar' }
}, (err, result) => {
if (err) console.log(err)
})
```
The returned value of **every** API call is formed as follows:
```ts
{
body: object | boolean
statusCode: number
headers: object
warnings: [string]
meta: object
}
```
### Client options
The client is designed to be easily configured as you see fit for your needs, following you can see all the possible options that you can use to configure it.
```ts
{
// the Elasticsearch endpoint to use
node: string | string[];
// alias of above
nodes: string | string[];
// custom connection class
Connection: typeof Connection;
// custom connection pool class
ConnectionPool: typeof ConnectionPool;
// custom transport class
Transport: typeof Transport;
// custom serializer class
Serializer: typeof Serializer;
// max number of retries for each request
maxRetries: number;
// max request timeout for each request
requestTimeout: number;
// max ping timeout for each request
pingTimeout: number;
// perform a sniff operation every `n` milliseconds
sniffInterval: number;
// perform a sniff once the client is started
sniffOnStart: boolean;
// custom sniff endpoint, defaults `_nodes/_all/http`
sniffEndpoint: string;
// perform a sniff on connection fault
sniffOnConnectionFault: boolean;
// configurethe node resurrection strategy, default `ping`
resurrectStrategy: 'ping' | 'optimistic' | 'none';
// adds `accept-encoding` header to every request
suggestCompression: boolean;
// enable gzip request body compression
compression: 'gzip';
// ssl configuraton
ssl: http.SecureContextOptions;
// http agent options
agent: http.AgentOptions;
// filters which node not to use for a request
nodeFilter: nodeFilterFn;
// custom selection strategy, defaults `round-robin`
nodeSelector: nodeSelectorFn | string;
// function to generate the request id for every request
generateRequestId: generateRequestIdFn;
// name to identify the client instance in the events
name: string;
}
```
### Request specific options
If needed you can pass request specific options in a second object:
```js
// promise API
const result = await client.search({
index: 'my-index',
body: { foo: 'bar' }
}, {
ignore: [404],
maxRetries: 3
})
```
The supported *request specific options* are:
```ts
{
ignore: [number], // default `null`
requestTimeout: number, // client default
maxRetries: number, // default `5`
asStream: boolean, // default `false`
compression: string, // default `false`
headers: object, // default `null`
querystring: object // default `null`,
context: object // default `null`,
id: any // default incr. integer
}
```
## License
This software is licensed under the [Apache 2 license](./LICENSE).