nested emit call in a queue should be handled in FIFO

Summary: I think we should dispose events in FIFO order

Reviewed By: fkgozali

Differential Revision: D2987425

fb-gh-sync-id: a4ad256512725d0bed0086b642e10fe7e7715070
shipit-source-id: a4ad256512725d0bed0086b642e10fe7e7715070

Libraries/CustomComponents/Navigator/Navigation/NavigationEventEmitter.js

@@ -59,7 +59,7 @@ class NavigationEventEmitter extends EventEmitter {
       // An event cycle that was previously created hasn't finished yet.
       // Put this event cycle into the queue and will finish them later.
       var args: any = Array.prototype.slice.call(arguments);
-      this._emitQueue.unshift(args);
+      this._emitQueue.push(args);
       return;
     }
 

Libraries/CustomComponents/Navigator/Navigation/__tests__/NavigationEventEmitter-test.js

@@ -100,6 +100,32 @@ describe('NavigationEventEmitter', () => {
     expect(logs).toEqual([1, 2, 3, 4, 5]);
   });
 
+  it('puts nested emit call in a queue should be in sequence order', () => {
+    var context = {};
+    var emitter = new NavigationEventEmitter(context);
+    var logs = [];
+
+    emitter.addListener('one', () => {
+      logs.push(1);
+      emitter.emit('two');
+      emitter.emit('three');
+      logs.push(2);
+    });
+
+    emitter.addListener('two', () => {
+      logs.push(3);
+      logs.push(4);
+    });
+
+    emitter.addListener('three', () => {
+      logs.push(5);
+    });
+
+    emitter.emit('one');
+
+    expect(logs).toEqual([1, 2, 3, 4, 5]);
+  });
+
   it('calls callback after emitting', () => {
     var context = {};
     var emitter = new NavigationEventEmitter(context);