types relations problem

gistfile1.txt

// { type: 'A', payload: { timestamp: number } }
// { type: 'B', payload: { user_id: string } }

const parseA = data => ({ lastTimestamp: data * 1000 })
const parseB = data => ({ userId: data })

const serverMessageParser = (msg: SocketMessage): ParsedMessage => {
	switch (msg.action) {
	case 'A':
		return parseA(msg.data)
	case 'B':
		return parseB(msg.data)
	}
}

socket.on('message', (msg: SocketMessage) => {
	store.dispatch({
		type: 'push_received',
		payload: {
			action: msg.action,
			data: serverMessageParser(msg)
		}
	})
})

const sideEffectsMiddleware = (action: Action, store: Store) => {
	switch (action.type) {
	case 'push_received':
		emitter.emit(action.payload.action, action.payload.data)
		return
	}
}