feat(utilities): add support for custom styles beginning with "--*"

Author: samikarak

lib/utilities.js

@@ -1,5 +1,6 @@
 var React = require('react');
 var hyphenPatternRegex = /-([a-z])/g;
+var CUSTOM_PROPERTY_OR_NO_HYPHEN_REGEX = /^--[a-zA-Z-]+$|^[^-]+$/;
 
 /**
  * Converts a string to camelCase.
@@ -12,8 +13,8 @@ function camelCase(string) {
     throw new TypeError('First argument must be a string');
   }
 
-  // no hyphen found
-  if (string.indexOf('-') === -1) {
+  // custom property or no hyphen found
+  if (CUSTOM_PROPERTY_OR_NO_HYPHEN_REGEX.test(string)) {
     return string;
   }
 

test/utilities.js

@@ -20,6 +20,8 @@ describe('utilties.camelCase', () => {
     assert.equal(camelCase(''), '');
     assert.equal(camelCase('foo'), 'foo');
     assert.equal(camelCase('fooBar'), 'fooBar');
+    assert.equal(camelCase('--fooBar'), '--fooBar');
+    assert.equal(camelCase('--foo-bar'), '--foo-bar');
   });
 
   it('camelCases a string', () => {