Typescript errors creating custom transport

[chadjaros]

Please tell us about your environment:

• winston version? 3.0.0
  • winston@2
  • winston@3
• node -v outputs: v8.9.4
• Operating System? macOS
• Language? TypeScript 2.9.2

What is the problem?

I'm trying to declare a new custom Transport.

import Transport from 'winston-transport';

export class CustomLogger extends Transport {
  constructor(opts: any) {
    super(opts);
  }
  log(info, callback) {
    setImmediate(() => {
      this.emit('logged', info);
    });

    // Log Stuff

    if (callback) {
      callback();
    }
  }
}

I am seeing 2 compiler errors:

From import Transport from 'winston-transport';

error TS1192: Module '".../node_modules/winston-transport/index"' has no default export.

In 3.0.0-rc5 this could be worked around by doing

import * as winston from 'winston';

class Foo extends winston.Transport {
...

---

From this.emit('logged', info);

error TS2339: Property 'emit' does not exist on type 'AirbrakeLogger'.

I can work around this by doing (this as any).emit('logged', info);, but it's not pretty.

What do you expect to happen instead?

No compiler errors?

Other information

[DABH]

If I take your example, npm install winston-transport, and import * as Transport from winston-transport, all seems to work well. Let me know if that doesn't work for you or if you have other issues. Thanks!

[opensas]

I'm facing a similar issue here.

My code:

import * as Transport from 'winston-transport'
// import Transport from 'winston-transport';

export class CustomLogger extends Transport {
  constructor(opts: any) {
    super(opts);
  }
  log(info, callback) {
    setImmediate(() => {
      this.emit('logged', info);
    });

    // Log Stuff
    if (callback) {
      callback();
    }
  }
}

and i get:

lib/CustomLogger.ts:4:35 - error TS2507: Type 'typeof TransportStream' is not a constructor function type.

4 export class CustomLogger extends Transport {

lib/CustomLogger.ts:8:7 - error TS7006: Parameter 'info' implicitly has an 'any' type.

8   log(info, callback) {

lib/CustomLogger.ts:8:13 - error TS7006: Parameter 'callback' implicitly has an 'any' type.

8   log(info, callback) {

lib/CustomLogger.ts:10:12 - error TS2339: Property 'emit' does not exist on type 'CustomLogger'.

10       this.emit('logged', info);

Found 4 errors.

using:

  "dependencies": {
    "winston": "^3.2.1",
    "winston-transport": "^4.3.0"
  },
  "devDependencies": {
    "@types/node": "^12.0.7",
    "typescript": "^3.5.1"
  }

more info:

λ node --version
v12.1.0

λ npm --version
6.9.0

Also asked at stack overflow

[charlie-harvey]

Still happening in 2022. I have the exact same error as @opensas

  "dependencies": {
    "winston": "3.7.2",
    "winston-transport": "4.5.0"
  },
  "devDependencies": {
    "typescript": "4.7.2"
  }

λ node --version
v14.19.1

λ npm --version
6.14.6

Fixed

import Transport from 'winston-transport';