fix module export for class

[aoberoi]

As described in #104, I was having issues with the type definitions. I made these changes locally and it worked. My only concern is I don't have a great idea about backwards compatibility with older versions of the typescript compiler (I'm using 2.7.1 -- the latest stable).

see: https://www.typescriptlang.org/docs/handbook/declaration-files/templates/module-class-d-ts.html

[aoberoi]

Ping @delta62. It looks like you might be the resident TypeScript expert for this project

[aoberoi]

The failure above seems unrelated, and has something to do with Sauce Labs.

[lpinca]

Ignore the failure. Encrypted environment variables are not available to pull requests from forks due to the security risk of exposing such information to unknown code.

[lpinca]

cc: @Stubb0rn

[delta62]

Okay, so it seems there are a few test cases to follow through on here:

• Use TS 2.7 with the new esModuleInterop flag, importing as a default import
• Use TS 2.7 with the new esModuleInterop flag, importing as a named import
• Use TS 2.7 with the new esModuleInterop flag, importing using import = require
• Use TS 2.6 using a named import
• Use TS 2.6 using import = require
• Use any TS version to ensure that EventEmitter is not leaked as a globally defined construct without explicitly importing it

We could also test 2.7 without the esModuleInterop stuff, but I think that's going to be redundant if we test it in 2.6.

[delta62]

It doesn't look like named imports (import { EventEmitter } from 'eventemitter3') are working with this build.

I can spend some time this week fixing it up, or you can take another stab at it @aoberoi!

[delta62]

@aoberoi I've created a PR into your feature branch that should clear up the issues.

[aoberoi]

thanks @delta62! just merged, so this PR should inherit the change :)

[lpinca]

@aoberoi @delta62 thank you!

[dcharbonnier]

this break my build ;-)

lib/IConnectionDriver.ts(3,44): error TS2304: Cannot find name 'EventEmitter'.
lib/IConnectionDriver.ts(3,44): error TS4022: 'extends' clause of exported interface 'IConnectionDriver' has or is using private name 'EventEmitter'.

The solution is to replace :
import { EventEmitter } from "eventemitter3";

With import * as EventEmitter from "eventemitter3";

[lpinca]

Ops, sorry about that. Happy to cut a new release if you know how to fix that :)

[delta62]

@dcharbonnier Could you include your tsconfig.json so that we can look into fixing this for other people with your setup?

[yahyavi]

I have a similar problem as @dcharbonnier

[delta62]

Hi @yahyavi. Could you please post your tsconfig.json? I have a test repository that seems to be working for both 2.6 and 2.7, so I'm guessing something specific to the setup you guys are using causes the issue.

[yahyavi]

Sure, here you go:

{
    "compilerOptions": {
        "allowJs": true,
        "module": "commonjs",
        "lib": [
            "dom",
            "es6",
        ],
        "target": "es6",
        "sourceMap": true
    },
    "include": [
        "./src/**/*"
    ]
}

[delta62]

Thanks a lot! In this particular case, the code is working as I would expect.

// This works
// import * as EventEmitter from 'eventemitter3'

// This works
// import { EventEmitter } from 'eventemitter3'

// This works
// import EventEmitter = require('eventemitter3')

// This works with esModuleInterop = true
// import EventEmitter from 'eventemitter3'

const emitter = new EventEmitter()
emitter.on('some-event', () => console.log('success!'))
emitter.emit('some-event')

But maybe I'm missing something, or you had a different use-case in mind?

edit: added import = example

[yahyavi]

In my case import * as EventEmitter from 'eventemitter3' works but import { EventEmitter } from 'eventemitter3' does not.
Could be a webpack issue?

[delta62]

Ah, that would make sense. If I recall correctly, WebPack makes use of Babel to bundle the files under the hood, so there could be a configuration difference between WebPack and TypeScript.

[yahyavi]

Yeah, my guess this release broke something with webpack, because before that import { EventEmitter } from 'eventemitter3' was working fine.

[delta62]

Hmm, I still can't repro this.

I created a webpack / ts-loaderproject, and I can still import in any of the ways mentioned above. I updated my sample project to reflect this (see the webpack branch).

It sounds like you've got a workaround for this, so let's open a new issue if we need to continue debugging!

[yahyavi]

I have a deadline right now. Will try to have a look at the sample project in a couple of weeks.

[shaharmor]

This change breaks extending EventEmitter3:

import { EventEmitter } from 'eventemitter3';


export class MyEmitter extends EventEmitter {
  public constructor() {
    super();
  }
}

results in the following error: Base constructor return type '() => EventEmitter' is not a class or interface type

[delta62]

Hi @shaharmor!

I put the sample code you have above into my test project and it's compiling ok. I am using eventemitter3@3.0.1 / typescript@2.7.1. Maybe we have different build environments?

If you're still able to repro, let's open a new ticket to track this 🙂