From a2359a7c229db3bc111f47a86c889216951162ef Mon Sep 17 00:00:00 2001
From: Angelos Chalaris <chalarangelo@gmail.com>
Date: Sun, 31 Dec 2017 14:20:21 +0200
Subject: [PATCH] Add isPromise snippet

---
 snippets/isPromise.md | 16 ++++++++++++++++
 tag_database          |  1 +
 2 files changed, 17 insertions(+)
 create mode 100644 snippets/isPromise.md

diff --git a/snippets/isPromise.md b/snippets/isPromise.md
new file mode 100644
index 000000000..7a6e32d3f
--- /dev/null
+++ b/snippets/isPromise.md
@@ -0,0 +1,16 @@
+### isPromise
+
+Returns `true` if an object looks like a [`Promise`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Promise), `false` otherwise.
+
+Check if the object is not `null`, its `typeof` matches either `object` or `function` and if it has a `.then` property, which is also a `function`.
+
+```js
+const isPromise = obj =>
+  obj !== null && (typeof obj === 'object' || typeof obj === 'function') && typeof obj.then === 'function';
+```
+
+```js
+isPromise({then:function () {return ''}}); // true
+isPromise(null); // false
+isPromise({}); // false
+```
diff --git a/tag_database b/tag_database
index e2bb75c7e..5c9edee5d 100644
--- a/tag_database
+++ b/tag_database
@@ -73,6 +73,7 @@ isFunction:utility
 isNull:utility
 isNumber:utility
 isPrime:math
+isPromise:utility
 isString:utility
 isSymbol:utility
 JSONToDate:date