Node-Redis

node-redis is a modern, high performance Redis client for Node.js with built-in support for Redis 6.2 commands and modules including RediSearch and RedisJSON.

Installation

npm install redis

⚠️ The new interface is clean and cool, but if you have an existing codebase, you'll want to read the migration guide.

Usage

Basic Example

import { createClient } from 'redis';

(async () => {
  const client = createClient();

  client.on('error', (err) => console.log('Redis Client Error', err));

  await client.connect();

  await client.set('key', 'value');
  const value = await client.get('key');
})();

The above code connects to localhost on port 6379. To connect to a different host or port, use a connection string in the format redis[s]://[[username][:password]@][host][:port][/db-number]:

createClient({
  url: 'redis://alice:[email protected]:6380'
});

You can also use discrete parameters, UNIX sockets, and even TLS to connect. Details can be found in the client configuration guide.

Redis Commands

There is built-in support for all of the out-of-the-box Redis commands. They are exposed using the raw Redis command names (HSET, HGETALL, etc.) and a friendlier camel-cased version (hSet, hGetAll, etc.):

// raw Redis commands
await client.HSET('key', 'field', 'value');
await client.HGETALL('key');

// friendly JavaScript commands
await client.hSet('key', 'field', 'value');
await client.hGetAll('key');

Modifiers to commands are specified using a JavaScript object:

await client.set('key', 'value', {
  EX: 10,
  NX: true
});

Replies will be transformed into useful data structures:

await client.hGetAll('key'); // { field1: 'value1', field2: 'value2' }
await client.hVals('key'); // ['value1', 'value2']

Unsupported Redis Commands

If you want to run commands and/or use arguments that Node Redis doesn't know about (yet!) use .sendCommand():

await client.sendCommand(['SET', 'key', 'value', 'NX']); // 'OK'

await client.sendCommand(['HGETALL', 'key']); // ['key1', 'field1', 'key2', 'field2']

Transactions (Multi/Exec)

Start a transaction by calling .multi(), then chaining your commands. When you're done, call .exec() and you'll get an array back with your results:

await client.set('another-key', 'another-value');

const [setKeyReply, otherKeyValue] = await client
  .multi()
  .set('key', 'value')
  .get('another-key')
  .exec(); // ['OK', 'another-value']

You can also watch keys by calling .watch(). Your transaction will abort if any of the watched keys change.

To dig deeper into transactions, check out the Isolated Execution Guide.

Blocking Commands

Any command can be run on a new connection by specifying the isolated option. The newly created connection is closed when the command's Promise is fulfilled.

This pattern works especially well for blocking commands—such as BLPOP and BLMOVE:

import { commandOptions } from 'redis';

const blPopPromise = client.blPop(commandOptions({ isolated: true }), 'key', 0);

await client.lPush('key', ['1', '2']);

await blPopPromise; // '2'

To learn more about isolated execution, check out the guide.

Pub/Sub

Subscribing to a channel requires a dedicated stand-alone connection. You can easily get one by .duplicate()ing an existing Redis connection.

const subscriber = client.duplicate();

await subscriber.connect();

Once you have one, simply subscribe and unsubscribe as needed:

await subscriber.subscribe('channel', (message) => {
  console.log(message); // 'message'
});

await subscriber.pSubscribe('channe*', (message, channel) => {
  console.log(message, channel); // 'message', 'channel'
});

await subscriber.unsubscribe('channel');

await subscriber.pUnsubscribe('channe*');

Publish a message on a channel:

await publisher.publish('channel', 'message');

There is support for buffers as well:

await subscriber.subscribe('channel', (message) => {
  console.log(message); // <Buffer 6d 65 73 73 61 67 65>
}, true);

await subscriber.pSubscribe('channe*', (message, channel) => {
  console.log(message, channel); // <Buffer 6d 65 73 73 61 67 65>, <Buffer 63 68 61 6e 6e 65 6c>
}, true);

Scan Iterator

SCAN results can be looped over using async iterators:

for await (const key of client.scanIterator()) {
  // use the key!
  await client.get(key);
}

This works with HSCAN, SSCAN, and ZSCAN too:

for await (const { field, value } of client.hScanIterator('hash')) {}
for await (const member of client.sScanIterator('set')) {}
for await (const { score, value } of client.zScanIterator('sorted-set')) {}

You can override the default options by providing a configuration object:

client.scanIterator({
  TYPE: 'string', // `SCAN` only
  MATCH: 'patter*',
  COUNT: 100
});

Lua Scripts

Define new functions using Lua scripts which execute on the Redis server:

import { createClient, defineScript } from 'redis';

(async () => {
  const client = createClient({
    scripts: {
      add: defineScript({
        NUMBER_OF_KEYS: 1,
        SCRIPT:
          'local val = redis.pcall("GET", KEYS[1]);' +
          'return val + ARGV[1];',
        transformArguments(key: string, toAdd: number): Array<string> {
          return [key, toAdd.toString()];
        },
        transformReply(reply: number): number {
          return reply;
        }
      })
    }
  });

  await client.connect();

  await client.set('key', '1');
  await client.add('key', 2); // 3
})();

Disconnecting

There are two functions that disconnect a client from the Redis server. In most scenarios you should use .quit() to ensure that pending commands are sent to Redis before closing a connection.

`.QUIT()`/`.quit()`

Gracefully close a client's connection to Redis, by sending the QUIT command to the server. Before quitting, the client executes any remaining commands in its queue, and will receive replies from Redis for each of them.

const [ping, get, quit] = await Promise.all([
  client.ping(),
  client.get('key'),
  client.quit()
]); // ['PONG', null, 'OK']

try {
  await client.get('key');
} catch (err) {
  // ClosedClient Error
}

`.disconnect()`

Forcibly close a client's connection to Redis immediately. Calling disconnect will not send further pending commands to the Redis server, or wait for or parse outstanding responses.

await client.disconnect();

Auto-Pipelining

Node Redis will automatically pipeline requests that are made during the same "tick".

client.set('Tm9kZSBSZWRpcw==', 'users:1');
client.sAdd('users:1:tokens', 'Tm9kZSBSZWRpcw==');

Of course, if you don't do something with your Promises you're certain to get unhandled Promise exceptions. To take advantage of auto-pipelining and handle your Promises, use Promise.all().

await Promise.all([
  client.set('Tm9kZSBSZWRpcw==', 'users:1'),
  client.sAdd('users:1:tokens', 'Tm9kZSBSZWRpcw==')
]);

Clustering

Check out the Clustering Guide when using Node Redis to connect to a Redis Cluster.

Events

The Node Redis client class is an Nodejs EventEmitter and it emits an event each time the network status changes:

Event name	Scenes	Parameters
connect	The client is initiating a connection to the server.	undefined
ready	The client successfully initiated the connection to the server.	undefined
end	The client disconnected the connection to the server via `.quit()` or `.disconnect()`.	undefined
error	When a network error has occurred, such as unable to connect to the server or the connection closed unexpectedly.	The error object, such as `SocketClosedUnexpectedlyError: Socket closed unexpectedly` or `Error: connect ECONNREFUSED [IP]:[PORT]`
reconnecting	The client is trying to reconnect to the server.	undefined