chore(DeferObservable): add benchmarks & minor perf

perf/micro/current-thread-scheduler/observable/defer.js

@@ -0,0 +1,25 @@
+var RxOld = require('rx');
+var RxNew = require('../../../../index');
+
+module.exports = function empty(suite) {
+  var oldObservableWithCurrentThreadScheduler = RxOld.Observable.empty(RxOld.Scheduler.currentThread);
+  var newObservableWithCurrentThreadScheduler = RxNew.Observable.empty(RxNew.Scheduler.queue);
+
+  function oldFactory() { return oldObservableWithCurrentThreadScheduler; }
+  function newFactory() { return newObservableWithCurrentThreadScheduler; }
+
+  var oldDeferWithCurrentThreadScheduler = RxOld.Observable.defer(oldFactory);
+  var newDeferWithCurrentThreadScheduler = RxNew.Observable.defer(newFactory);
+
+  function _next(x) { }
+  function _error(e) { }
+  function _complete() { }
+  // add tests
+  return suite
+    .add('old defer with current thread scheduler', function () {
+      oldDeferWithCurrentThreadScheduler.subscribe(_next, _error, _complete);
+    })
+    .add('new defer with current thread scheduler', function () {
+      newDeferWithCurrentThreadScheduler.subscribe(_next, _error, _complete);
+    });
+};

perf/micro/immediate-scheduler/observable/defer.js

@@ -0,0 +1,25 @@
+var RxOld = require('rx');
+var RxNew = require('../../../../index');
+
+module.exports = function empty(suite) {
+  var oldObservableWithImmediateScheduler = RxOld.Observable.empty(RxOld.Scheduler.immediate);
+  var newObservableWithImmediateScheduler = RxNew.Observable.empty();
+
+  function oldFactory() { return oldObservableWithImmediateScheduler; }
+  function newFactory() { return newObservableWithImmediateScheduler; }
+
+  var oldDeferWithImmediateScheduler = RxOld.Observable.defer(oldFactory);
+  var newDeferWithImmediateScheduler = RxNew.Observable.defer(newFactory);
+
+  function _next(x) { }
+  function _error(e) { }
+  function _complete() { }
+  // add tests
+  return suite
+    .add('old defer with immediate scheduler', function () {
+      oldDeferWithImmediateScheduler.subscribe(_next, _error, _complete);
+    })
+    .add('new defer with immediate scheduler', function () {
+      newDeferWithImmediateScheduler.subscribe(_next, _error, _complete);
+    });
+};

src/observable/DeferObservable.ts

@@ -73,12 +73,16 @@ class DeferSubscriber<T> extends OuterSubscriber<T, T> {
 
   private tryDefer(): void {
     try {
-      const result = this.factory.call(this);
-      if (result) {
-        this.add(subscribeToResult(this, result));
-      }
+      this._callFactory();
     } catch (err) {
       this._error(err);
     }
   }
+
+  private _callFactory(): void {
+    const result = this.factory();
+    if (result) {
+      this.add(subscribeToResult(this, result));
+    }
+  }
 }