Fix deep equal comparison between promises (#217)

sinonjs · May 24, 2021 · 144204d · 144204d
1 parent ee77305
commit 144204d
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diff --git a/.eslintrc.yaml b/.eslintrc.yaml
@@ -9,6 +9,7 @@ rules:
 
 globals:
   BigInt: false
+  Promise: false
   Int8Array: false
   Uint8Array: false
   Uint8ClampedArray: false

diff --git a/lib/deep-equal.js b/lib/deep-equal.js
@@ -117,6 +117,10 @@ function deepEqualCyclic(actual, expectation, match) {
             }
         }
 
+        if (actualObj instanceof Promise && expectationObj instanceof Promise) {
+            return actualObj === expectationObj;
+        }
+
         if (actualObj instanceof Error && expectationObj instanceof Error) {
             return actualObj === expectationObj;
         }

diff --git a/lib/deep-equal.test.js b/lib/deep-equal.test.js
@@ -909,4 +909,19 @@ describe("deepEqual", function () {
             });
         });
     });
+
+    describe("promises", function () {
+        it("returns true if the same promise instance is compared", function () {
+            var promise = Promise.resolve();
+            var checkDeep = samsam.deepEqual(promise, promise);
+            assert.isTrue(checkDeep);
+        });
+
+        it("returns false if a different promise instance is compared", function () {
+            var promise1 = Promise.resolve();
+            var promise2 = Promise.resolve();
+            var checkDeep = samsam.deepEqual(promise1, promise2);
+            assert.isFalse(checkDeep);
+        });
+    });
 });