Provide separate auto-polyfill version of this module

This commit provides a mechanism for users to load a version of this
module which automatically installs the polyfill, separately from the
default non-automatic version, as outlined in
#126 (comment)

It uses require('es6-promise/auto') instead of
require('es6-promise/polyfil') so that it does not directly conflict
with the es-shim-api API Contract[1], in case support is later added.

In addition to the Node/Browserify file, a UMD file which triggers
automatic polyfill installation is also provided.

Fixes: #140
Alternative-to: #126

1.  https://github.com/es-shims/es-shim-api#api-contract

Signed-off-by: Kevin Locke <[email protected]>

Author: kevinoid

Brocfile.js

@@ -59,12 +59,24 @@ var header = stew.map(find('config/versionTemplate.txt'), function(content) {
   return content.replace(/VERSION_PLACEHOLDER_STRING/, version());
 });
 
+var dist = es6Promise;
+
 function concatAs(tree, outputFile) {
-  return concat(merge([tree, header]), {
-    headerFiles: ['config/versionTemplate.txt'],
-    inputFiles:  ['es6-promise.js'],
-    outputFile: outputFile
-  });
+  return merge([
+    concat(merge([tree, header]), {
+      headerFiles: ['config/versionTemplate.txt'],
+      inputFiles:  ['es6-promise.js'],
+      outputFile: outputFile
+    }),
+
+    concat(merge([tree, header]), {
+      headerFiles: ['config/versionTemplate.txt'],
+      inputFiles:  ['es6-promise.js'],
+      outputFile: outputFile.replace('es6-promise', 'es6-promise.auto'),
+      footer:    'ES6Promise.polyfill();',
+    }),
+
+  ]);
 }
 
 function production(dist, header) {

README.md

@@ -6,8 +6,10 @@ For API details and how to use promises, see the <a href="http://www.html5rocks.
 
 ## Downloads
 
-* [es6-promise 27.86 KB (7.33 KB gzipped)](https://raw.githubusercontent.com/stefanpenner/es6-promise/master/dist/es6-promise.js)
-* [es6-promise-min 6.17 KB (2.4 KB gzipped)](https://raw.githubusercontent.com/stefanpenner/es6-promise/master/dist/es6-promise.min.js)
+* [es6-promise 27.86 KB (7.33 KB gzipped)](https://raw.githubusercontent.com/stefanpenner/es6-promise/master/dist/lib/es6-promise.js)
+* [es6-promise-auto 27.78 KB (7.3 KB gzipped)](https://raw.githubusercontent.com/stefanpenner/es6-promise/master/dist/es6-promise.auto.js) - Automatically provides/replaces `Promise` if missing or broken.
+* [es6-promise-min 6.17 KB (2.4 KB gzipped)](https://raw.githubusercontent.com/stefanpenner/es6-promise/master/dist/lib/es6-promise.min.js)
+* [es6-promise-auto-min 6.19 KB (2.4 KB gzipped)](https://raw.githubusercontent.com/stefanpenner/es6-promise/master/dist/es6-promise.auto.min.js) - Minified version of `es6-promise-auto` above.
 
 ## Node.js
 
@@ -23,6 +25,12 @@ To use:
 var Promise = require('es6-promise').Promise;
 ```
 
+
+```js
+require('es6-promise/auto');
+Promise;
+```
+
 ## Bower
 
 To install:
@@ -60,6 +68,12 @@ To polyfill the global environment (either in Node or in the browser via CommonJ
 require('es6-promise').polyfill();
 ```
 
+Alternatively
+
+```js
+require('es6-promise/auto');
+```
+
 Notice that we don't assign the result of `polyfill()` to any variable. The `polyfill()` method will patch the global environment (in this case to the `Promise` name) when called.
 
 ## Building & Testing

auto.js

@@ -0,0 +1,4 @@
+// This file can be required in Browserify and Node.js for automatic polyfill
+// To use it:  require('es6-promise/auto');
+'use strict';
+module.exports = require('.').polyfill();