Merge branch 'feature/promises-a+' into develop

Author: json2d

README.md

@@ -81,5 +81,17 @@ async function foo(req,res) {
 }
 ```
 
+## Promises/A+ compliant support
+You never know what kind of promise you'll get from an external dependency. It can be from Bluebird, Babel polyfill or some other library. `on` should work with any promise object can `then`, such as the one provided by the popular [`bluebird`](https://github.com/petkaantonov/bluebird/) package:
+
+```
+const {on} = require('await-on');
+const Bluebird = require('bluebird')
+
+const fetchData = () => new Bluebird(/*...*/);
+const [err, data] = await on(fetchData());
+```
+
+
 ## License
 MIT License. See [License](https://github.com/bitstrider/await-on/blob/master/LICENSE) in the repository.

lib/await-on.js

@@ -6,7 +6,7 @@
  * @return {Array}              Array with signature `[err, data]`
  */
 function on(promise) {
-  if(promise instanceof Promise) {
+  if(promise && typeof promise.then === 'function') {
     return promise.then(data => {
       return [null, data];
     })

package-lock.json

@@ -28,6 +28,7 @@
   "author": "Jason Yung",
   "license": "MIT",
   "devDependencies": {
+    "bluebird": "^3.5.4",
     "tap": "^10.7.2"
   },
   "engines": {

package.json

@@ -1,9 +1,10 @@
 const tap = require('tap')
+const Bluebird = require('bluebird')
 const on = require('../lib/await-on')
 const ANSWER = 42
 const ERROR = new Error('Need more time to figure that out')
 
-let waitOne = (answer=ANSWER) => new Promise(resolve => setTimeout(() => resolve(answer),1000))
+let waitOne = (answer=ANSWER, PromiseConstructor = Promise) => new PromiseConstructor(resolve => setTimeout(() => resolve(answer),10))
 let waitOneAndThrow = () => waitOne().then(res => Promise.reject(ERROR))
 
 tap.test("on", async function (t) {
@@ -15,6 +16,15 @@ tap.test("on", async function (t) {
 	t.equal(res,ANSWER)
 })
 
+tap.test("on thenable", async function (t) {
+  t.plan(2)
+
+	const [err,res] = await on(waitOne(ANSWER, Bluebird))
+
+	t.notOk(err)
+	t.equal(res,ANSWER)
+})
+
 tap.test("@handler", async function (t) {
   t.plan(2)