Add ReactNativeDispatcher

kotlinx-coroutines-core/js/src/CoroutineContext.kt

@@ -14,9 +14,12 @@ internal actual fun createDefaultDispatcher(): CoroutineDispatcher = when {
     // Check if we are in the browser and must use window.postMessage to avoid setTimeout throttling
     jsTypeOf(window) != UNDEFINED && window.asDynamic() != null && jsTypeOf(window.asDynamic().addEventListener) != UNDEFINED ->
         window.asCoroutineDispatcher()
+    // On react-native use setImmediate
+    jsTypeOf(navigator) != UNDEFINED && navigator != null && navigator.product == "ReactNative" ->
+        ReactNativeDispatcher
     // If process is undefined (e.g. in NativeScript, #1404), use SetTimeout-based dispatcher
     jsTypeOf(process) == UNDEFINED || jsTypeOf(process.nextTick) == UNDEFINED -> SetTimeoutDispatcher
-    // Fallback to NodeDispatcher when browser environment is not detected
+    // Fallback to NodeDispatcher when browser or react native environment is not detected
     else -> NodeDispatcher
 }
 

kotlinx-coroutines-core/js/src/JSDispatcher.kt

@@ -39,6 +39,12 @@ internal object NodeDispatcher : SetTimeoutBasedDispatcher() {
     }
 }
 
+internal object ReactNativeDispatcher : SetTimeoutBasedDispatcher() {
+    override fun scheduleQueueProcessing() {
+        setImmediate(messageQueue.processQueue)
+    }
+}
+
 internal actual class WindowMessageQueue actual constructor(private val window: W3CWindow) : MessageQueue() {
     private val messageName = "dispatchCoroutine"
 
@@ -66,5 +72,7 @@ private external fun setTimeout(handler: dynamic, timeout: Int = definedExternal
 
 private external fun clearTimeout(handle: Int = definedExternally)
 
+private external fun setImmediate(f: () -> Unit)
+
 private fun setTimeout(window: Window, handler: () -> Unit, timeout: Int): Int =
     window.setTimeout(handler, timeout)