How to make eventemitter3 typesafe

eventEmitterPattern.tsx

import EventEMitter3 from 'eventemitter3'

interface EmitterEvent<Type extends string> extends Object {
    type: Type;
}


interface AEvent extends EmitterEvent<'a'>{
    aOnly: true
}

interface BEvent extends EmitterEvent<'b'>{
    bOnly: true
}

type EmitterEvents = 
    | AEvent
    | BEvent

class Emitter extends EventEMitter3<EmitterEvents['type']> {
    on<Type extends EmitterEvents['type']>(name: Type, callback: (evt: Extract<EmitterEvents, {type: Type}>) => void) {
        return super.on(name, callback)
    }
    emit<Type extends EmitterEvents['type']>(name: Type, evt:  Omit<Extract<EmitterEvents, {type: Type}>, 'type'>) {
        return super.emit(name, evt)
    }
}

const em = new Emitter()
em.on('a', (evt) => {
    evt.aOnly
    // @ts-expect-error
    evt.bOnly
})

em.on('b', (evt) => {
    evt.bOnly
    // @ts-expect-error
    evt.aOnly
})

// @ts-expect-error
em.on('c', (evt) => {
    // c doesn't exist
})

em.emit('a', {aOnly: true})

// @ts-expect-error
em.emit('b', {aOnly: true})