Export TypeScript types from package

[sgoll]

For the recent version 4, the redis package includes TypeScript types but so far only the signatures of createClient(), commandOptions(), and createCluster() are exported (i.e. exported explicitly by name).

This makes it more difficult than necessary to use objects of the "public" types in custom code, such as:

class SomeClass {
  // Unable to declare this attribute:
  private redisClient: RedisClientType;
}

One workaround is to infer the types from the exported signatures:

// You _can_ get the type like this but this is hard to do for all types:
type RedisClientType = typeof redis.createClient extends () => infer ResultType
  ? ResultType
  : never;

I would suggest that index.ts should include at least exports of the most common types such as RedisClientType, RedisClientOptions, RedisClusterType, RedisClusterOptions, TuplesObject, option types for commands etc.

The only downside to this is that these types now form the public interface of the package API, i.e. may introduce breaking changes if later removed or renamed.

[leibale]

RedisClient/RedisClientType and RedisCluster/RedisClusterType can be extended with Redis modules & Lua Scripts, therefore in most cases the typeof operator is a better solution:

import { createClient } from '@node-redis/client';

export const client = createClient();

export type RedisClientType = typeof client;

[realpha]

Although I would also be in favor of exporting the client types directly instead of providing work arounds, the following also works if you can't/wont instantiate the client to obtain the interface:

import { createClient } from 'redis';

export type RedisClientType = ReturnType<typeof createClient>;

[jamesarosen]

I had to also explicitly coerce the result of createClient to RedisClientType:

export type RedisClientType = ReturnType<typeof createClient>

export default async function start(): Promise<RedisClientType> {
  const redis: RedisClientType = createClient({ url: … })
  await redis.connect()
  return redis
}

[tbinna]

The RedisClientType exported since 4.0.1 still does not work for me. Could not figure out how to make the exported RedisClientType, RedisClientOptions and the type returned by createClient compatible. Here is an example that illustrates the issue.

The following does not compile unless someone knows how to type RedisClientOptions correctly (refer to the code sandbox link above).

import { createClient, RedisClientOptions, RedisClientType } from "redis";

const factory = (options: RedisClientOptions<any, any>): RedisClientType => {
  return createClient(options);
};

const client: RedisClientType = factory({...});

Instead, I am doing this for now:

import { createClient} from "redis";
type RedisClientType = ReturnType<typeof createClient>;
type RedisClientOptions = Parameters<typeof createClient>[0];

const factory = (options: RedisClientOptions): RedisClientType => {
  return createClient(options);
};

const client: RedisClientType = factory({...});