RCTDeviceEventEmitter bridgeless alternative (Turbo Models)

[DanielFrTB]

@cipolleschi
Hi there,

I'm trying to send events from Turbo Models to the JS side. I understand that in the new architecture, EventDispatcher (react-native-menu/menu@247e0ec) is necessary. However, it requires a viewTag, which isn't available in Turbo Modules.

Is there a bridgeless alternative to RCTDeviceEventEmitter for sending events from Turbo Models (iOS and Android) ?

Thanks

#144

[DanielFrTB]

I see that pass a Callback is not valid since it used bridge

`

public String addUnitToPageAndroid(String pageId, String mode, String placement, Callback callback) {
});

package com.facebook.react.bridge;

public interface Callback {
void invoke(Object... var1);
}
`

[cipolleschi]

Have a look at this example. It uses swift but shows how to send events from Native to JS for iOS

[DanielFrTB]

@cipolleschi Thanks,
I can see in this example that RCTEventEmitter internally using @property (nonatomic, weak) RCTBridge *bridge;

Does it's mean that RCTEventEmitter is going to be deprecated ?

[cipolleschi]

uhm... you are right. the example uses 0.71, when bridgeless was not there yet. 🤔

Let me dig a little bit more into this.

[zerobertelprivat]

I am also totally interested in a solution to use events like implemented via RCTEventEmitter in the bridge mode. On JS Side i want to listen to a pure event, fired on the Native Side. For example, i need it to handle click interactions on Carplay Screen (init player and play music via RN Track Player). I found no fully understandable doc on the RN page. Thank you in advance :)

[cipolleschi]

@zerobertelprivat do you need to send an event in Bridge mode? why do you need a turbomodule?

For the time being, the best approach is:

• For the old architecture

  • in JS

  import {NativeEventEmitter} from 'react-native';
  
  // when you want to register a listener
  new NativeEventEmitter<YourEventPayload>().addListener('youreventName', data => {
    // do stuff
  }) 

  • in native, your module needs to extend RCTEventEmitter and the Java/Kt EventEmitter
  • then call the sendEventWithName method

• For the New Architecture we have the example

[zerobertelprivat]

Hi thanks for your answer :) -> I get emitting an event work for now.

In the example regarding the new Arch i am getting a TS Error ->

import type {EventEmitter} from 'react-native/Libraries/Types/CodegenTypes';
gives me
Module '"react-native/Libraries/Types/CodegenTypes"' has no exported member 'EventEmitter'.ts(2305)
Clicking on the import links me to the Codegen.d.ts file, which doesnt include this type.
Is it a bug or do i something wrong? I am on RN 0.76.1

Thanks nevertheless for your great work!

[cipolleschi]

Hum.. It should be there. This is the 0.76-branch with the EventEmitter definition.

Probably the import path is wrong. It should be 'react-native/types/modules/Codegen'.

[agoransson]

If upgrading to 0.76.3 the import seems to work.

import type {EventEmitter} from 'react-native/Libraries/Types/CodegenTypes';