From 144204d505526d5c382cb2f3dc2c2dd1378fe12d Mon Sep 17 00:00:00 2001
From: "David G. Miguel" <noxwings@gmail.com>
Date: Mon, 24 May 2021 21:00:46 +0200
Subject: [PATCH] Fix deep equal comparison between promises (#217)

---
 .eslintrc.yaml         |  1 +
 lib/deep-equal.js      |  4 ++++
 lib/deep-equal.test.js | 15 +++++++++++++++
 3 files changed, 20 insertions(+)

diff --git a/.eslintrc.yaml b/.eslintrc.yaml
index a1d8712..53ffe78 100644
--- 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
index c4241c9..f4fdfdd 100644
--- 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
index 5277cb9..a392578 100644
--- 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);
+        });
+    });
 });