"import Redis" is flagged as invalid constructor function type in ESM TypeScript project

[Sayakie]

I had to do this to get started

import Redis from 'ioredis'

import type { Species } from '#lib/pokemon/Species.js'

export enum RedisKey {
  GetPokemon = `getPokemon`
}

export type RedisQuery<K extends RedisKey> = K extends `getPokemon` ? Species : null

export class RedisClient extends Redis {
  public async insert<K extends RedisKey>(
    key: K,
    query: RedisQuery<K>,
    data: unknown
  ): Promise<`OK`> {
    return super.set(`${key}:${query}`, JSON.stringify(data))
  }
}

Same issue as:

import { default as Redis } from 'ioredis'

They prints: Type 'typeof import("node_modules/.pnpm/ioredis@5.2.3/node_modules/ioredis/built/index")' is not a constructor function type.

My project settings are:

package	version
Module Type	ESM
Node.js	16.13.2
pnpm	7.9.5
ioredis	5.2.3
TypeScript	4.8.2
@types/ioredis	not installed

TSConfig:

{
  "extends": "@sapphire/ts-config/extra-strict",
  "compilerOptions": {
    "lib": ["ESNext"],
    "target": "ESNext",
    "module": "ESNext",
    "moduleResolution": "Node16",
    "emitDecoratorMetadata": false
  }
}

[Sayakie]

Additional info for more context, new Redis() throws similar error: "This expression is not constructable. Type 'typeof import("node_modules/.pnpm/ioredis@5.2.3/node_modules/ioredis/built/index")' has no construct signatures."

[Sayakie]

Resolved as do:

import { default as Redis } from 'ioredis'

export class RedisClient extends Redis.default {
  // ... whatever
}

[GingerAdonis]

I'd say this issue should be re-opened as the workaround is kind of odd.

[Sayakie]

I'd say this issue should be re-opened as the workaround is kind of odd.

I assume would be better open a new ticket.

[GingerAdonis]

I'd say this issue should be re-opened as the workaround is kind of odd.

I assume would be better open a new ticket.

I disagree, as it would be a duplicate of this unresolved issue. But I'll do that if you don't want to open the issue.

[Sayakie]

@luin I re-open this issue because the behavior is odd and still would be problem.

Tracking of:

• TypeScript error: "This expression is not constructable" #1624
• Docs examples don't work with Typescript in ESM project #1632

[luin]

import { default as Redis } from "ioredis" is the solution documented on README.md but I agree the syntax may seem odd.

[GingerAdonis]

import { default as Redis } from "ioredis" is the solution documented on README.md but I agree the syntax may seem odd.

The problem is that despite using that import statement one still has to use Redis.default as a constructor to make it properly work with Typescript.

Example:

import { default as Redis } from 'ioredis';
const redis = new Redis.default();

The named Redis export is only exported as a type. Which is kind of strange as well.

[LinusU]

I can confirm that the normal import doesn't work when using moduleResolution node16 or nodenext. We are currently using the following workaround:

import RedisModule from 'ioredis'

// FIXME: https://github.com/luin/ioredis/issues/1642
const Redis = RedisModule.default

[huangyingjie]

I can confirm that the normal import doesn't work when using moduleResolution node16 or nodenext. We are currently using the following workaround:

import RedisModule from 'ioredis'

// FIXME: https://github.com/luin/ioredis/issues/1642
const Redis = RedisModule.default

I also use node16, and trapped by this @luin

[huangyingjie]

I can confirm that the normal import doesn't work when using moduleResolution node16 or nodenext. We are currently using the following workaround:

import RedisModule from 'ioredis'

// FIXME: https://github.com/luin/ioredis/issues/1642
const Redis = RedisModule.default

I also use node16, and trapped by this @luin

[huangyingjie]

I can confirm that the normal import doesn't work when using moduleResolution node16 or nodenext. We are currently using the following workaround:

import RedisModule from 'ioredis'

// FIXME: https://github.com/luin/ioredis/issues/1642
const Redis = RedisModule.default

I also use node16, and trapped by this @luin

[GingerAdonis]

Looks like this issue has been fixed in v5.2.5.

Issue can be closed.

[Sayakie]

Fixed in #1695