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v3-to-v4.md

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v3 to v4 Migration Guide

Version 4 of Node Redis is a major refactor. While we have tried to maintain backwards compatibility where possible, several interfaces have changed. Read this guide to understand the differences and how to implement version 4 in your application.

All of the Breaking Changes

See the Change Log.

Promises

Node Redis now uses native Promises by default for all functions.

createClient

The configuration object passed to createClient has changed significantly with this release. See the client configuration guide for details.

No Auto Connect

In V4, the client does not automatically connect to the server. Instead you need to run .connect() after creating the client or you will receive an error: ClientClosedError: The client is closed.

import { createClient } from 'redis';

const client = createClient();

await client.connect();

await client.ping();

All the removed events

The following events that existed in V3 were removed in V4:

  1. warning
  2. subscribe
  3. psubscribe
  4. unsubscribe
  5. message
  6. message_buffer
  7. messageBuffer
  8. pmessage
  9. pmessage_buffer
  10. pmessageBuffer
  11. monitor

No message-like event

In V4, you don't need to add a listener to the message-like events (items 5 to 10 of the above list), you can get the message directly in subscribe-like commands.

The second argument of these commands is a callback, which will be triggered every time there is a message published to the channel.

The third argument to these commands is a boolean to set bufferMode (default false). If it's set to true you will receive a buffer instead of a string.

The subscribe-like commands return a promise. If the command is executed successfully the promise will be fulfilled, otherwise the promise will be rejected.

import { createClient } from 'redis';

const subscriber = createClient();

await subscriber.connect();

await subscriber.subscribe('channel_name', (message, channelName) => {
    console.info(message, channelName);
});

Legacy Mode

Use legacy mode to preserve the backwards compatibility of commands while still getting access to the updated experience:

const client = createClient({
    legacyMode: true
});

// legacy mode
client.set('key', 'value', 'NX', (err, reply) => {
    // ...
});

// version 4 interface is still accessible
await client.v4.set('key', 'value', {
    NX: true
});