Handle returning any promise implementation

i20 · Apr 4, 2020 · f040422 · f040422
1 parent 4b54449
commit f040422
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Showing 2 changed files with 8 additions and 4 deletions.
diff --git a/Promise.es6.js b/Promise.es6.js
@@ -132,8 +132,10 @@ function Promise (_executor) {
 
                     const result = (_state === STATE_RESOLVED ? resolve || noopResolve : reject || noopReject)(_value);
 
-                    // If handler returns a promise then, it "replaces" the current promise
-                    if (result instanceof Promise)
+                    // If handler returns a promise then current promise resolution is bound to returned's one
+                    // Assimilate all thenable objects to handled returning a variety of other promise implementations
+                    // Natives, Qs, Bluebirds, ZoneAwarePromises ...
+                    if (result && typeof result.then === 'function')
                         result.then(nextResolve, nextReject, nextNotify);
 
                     else nextResolve(result);

diff --git a/Promise.js b/Promise.js
@@ -132,8 +132,10 @@ function Promise (_executor) {
 
                     var result = (_state === STATE_RESOLVED ? resolve || noopResolve : reject || noopReject)(_value);
 
-                    // If handler returns a promise then, it "replaces" the current promise
-                    if (result instanceof Promise)
+                    // If handler returns a promise then current promise resolution is bound to returned's one
+                    // Assimilate all thenable objects to handled returning a variety of other promise implementations
+                    // Natives, Qs, Bluebirds, ZoneAwarePromises ...
+                    if (result && typeof result.then === 'function')
                         result.then(nextResolve, nextReject, nextNotify);
 
                     else nextResolve(result);