From c2c32916363d84736d3655da46bc36212cf51e25 Mon Sep 17 00:00:00 2001
From: zsh <z1598192958@gmail.com>
Date: Mon, 28 Oct 2019 16:22:52 +0800
Subject: [PATCH] update isPromise function

---
 index.js | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/index.js b/index.js
index aacf6ef..542fb77 100644
--- a/index.js
+++ b/index.js
@@ -196,7 +196,7 @@ function objectToPromise(obj){
  */
 
 function isPromise(obj) {
-  return 'function' == typeof obj.then;
+  return !!obj && (typeof obj === 'object' && obj.__proto__ === Promise.prototype)
 }
 
 /**