Listener class is not being exported

[master30f]

Description The Listener class (and maybe some others) are not being exposed to the user, so it's impossible to use them in type definitions. Example:

import WebMidi from "webmidi"

class MidiManager {
    private activeListeners: WebMidi.Listener[] // Not possible -- Listener class is not exported

    ...
}

Environment:

• Library version and flavour: CJS 3.0.21
• Runtime: Browser (Webpack)
• Language: Typescript
• Operating system: Ubuntu Linux 20.04

Details None

[djipco]

The EventEmitter and Listener classes are actually part of the djipevents package which is separate from WEBMIDI.js. In such a case, I'm not sure what the proper way to do things is. To be honest, I'm not very familiar with TypeScript. Ideas?

[master30f]

I found that adding export before the class declaration in webmidi.cjs.d.ts like so:

export declare class Listener {
    ...
}

works as a very hackish work-around, but I'm not familiar with your build system (or any build systems in general as I've never made a ts library before) so I have no idea how to actually fix it.

Edit: I found out that in your case the declaration file is not auto generated, so applying the above fix to webmidi.d.ts might work.

[djipco]

As you noted, the Listener and EventEmitter classes are already declared in webmidi.d.ts but they are not exported. It was done this way because these two classes are actually part of a separate package called djipevents. If there is no harm in exporting them from webmidi.d.ts, I could easily do it. However, not being too familiar with TypeScript, I'm not sure of the implications. Could it cause unforeseen issues?

[master30f]

As far as I know it should not cause any harm, as the declarations in webmidi.d.ts are just typings -- they only tell the typescript compiler how the data structures "look" and will not collide with / override the javascript definitions.

[djipco]

This has been pushed in release v3.0.22. Thanks for suggesting this enhancement.