Merge pull request #630 from Chalarangelo/prefix

Create prefix.md

snippets/prefix.md

@@ -0,0 +1,19 @@
+### prefix
+
+Returns the prefixed version (if necessary) of a CSS property that the browser supports.
+
+Use `Array.findIndex()` on an array of vendor prefix strings to test if `document.body` has one of them defined in its `CSSStyleDeclaration` object, otherwise return `null`. 
+Use `String.charAt()` and `String.toUpperCase()` to capitalize the property, which will be appended to the vendor prefix string.
+
+```js
+const prefix = prop => {
+  const capitalizedProp = prop.charAt(0).toUpperCase() + prop.slice(1);
+  const prefixes = ['', 'webkit', 'moz', 'ms', 'o'];
+  const i = prefixes.findIndex(prefix => typeof document.body.style[(prefix ? prefix + capitalizedProp : prop)] !== 'undefined');
+  return i !== -1 ? i === 0 ? prop : prefixes[i] + capitalizedProp : null;
+}
+```
+
+```js
+prefix('appearance'); // 'appearance' on a supported browser, otherwise 'webkitAppearance', 'mozAppearance', 'msAppearance' or 'oAppearance'
+```