Uncaught TypeError: Cannot read property 'has' of undefined

[Lilja]

My usage, I'm using Ref because we are using Vue in this project.

const bus = ref(new Bus())
bus.value.emitter.on("newDataRequest", loadNewDataRequests)

loadNewDataRequests is of signature () => Promise<void>

[Lilja]

Removing ref() from the new Bus() call removes the side effect.

Here is the class for reference:

enum Events {
    NewDataRequest = "newDataRequest"
}
export class Bus {
    constructor() {
        this.emitter = new Emittery()
    }
    emitter: Emittery

    onNewDataRequest(callback: () => Promise<void>): void {
        this.emitter.on(Events.NewDataRequest, callback)
    }

    async newDataRequest(): Promise<void> {
       await this.emitter.emit(Events.NewDataRequest)
    }
}

[mattyg]

If anyone else is looking, one solution is to use toRaw():

const bus = ref(new Bus())
toRaw(bus.value).emitter.on("newDataRequest", loadNewDataRequests)

[ThetaSinner]

I've run into the same issue and documented what is happening here as it relates to the context I'm consuming the library in.

@sindresorhus please could you take a look at this issue and see if you agree with the proposed fix? In this library I'd think that binding any member function that accesses the global maps would be necessary, rather than just the 'on' that is needed in the linked issue. If you're happy with the proposal I'm happy to take on creating a PR for this library.

[georgzoeller]

Same is happening in alpine.js which uses proxies