From 50e4932ef4f065a777b6629c90db56310f89dd57 Mon Sep 17 00:00:00 2001
From: "Rico Sta. Cruz" <rstacruz@users.noreply.github.com>
Date: Thu, 26 Oct 2017 14:10:20 +0800
Subject: [PATCH] Add polyfill.io cheatsheet

---
 polyfill.io.md | 53 ++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 53 insertions(+)
 create mode 100644 polyfill.io.md

diff --git a/polyfill.io.md b/polyfill.io.md
new file mode 100644
index 000000000..41081ee6e
--- /dev/null
+++ b/polyfill.io.md
@@ -0,0 +1,53 @@
+---
+title: Polyfill.io
+category: JavaScript libraries
+updated: 2017-10-26
+layout: 2017/sheet
+intro: |
+  [Polyfill.io](https://polyfill.io) is a service that serves JavaScript polyfills.
+---
+
+## Usage
+
+### Default usage
+
+```html
+<script src="https://cdn.polyfill.io/v2/polyfill.min.js"></script>
+```
+{: .-wrap}
+
+This is the default script for Polyfill.io.
+
+### References
+
+- [API example](https://polyfill.io/v2/docs/api) _(polyfill.io)_
+- [List of features](https://polyfill.io/v2/docs/features) _(polyfill.io)_
+
+## Optimized
+
+### For modern browsers
+
+```html
+<script>(function(d,s){
+if(window.Promise&&[].includes&&Object.assign&&window.Map)return;
+var sc=d.getElementsByTagName(s)[0],js=d.createElement(s);
+js.src='https://cdn.polyfill.io/v2/polyfill.min.js';
+sc.parentNode.insertBefore(js, sc);
+}(document,'script'))</script>
+```
+
+This only includes polyfill.io when necessary, skipping it for modern browsers for faster load times.
+
+### Extra features
+
+```html
+<script>(function(d,s){
+if(window.fetch&&window.Promise&&[].includes&&Object.assign&&window.Map)return;
+var sc=d.getElementsByTagName(s)[0],js=d.createElement(s);
+js.src='https://cdn.polyfill.io/v2/polyfill.min.js?features=default,fetch';
+sc.parentNode.insertBefore(js, sc);
+}(document,'script'))</script>
+```
+{: data-line="2,4"}
+
+This is the same as the previous, but also adds a polyfill for `window.fetch()`. We add a `window.fetch` check and loads the additional `fetch` feature.