code: function camelize(str) {
    return str.replace(STRING_CAMELIZE_REGEXP_1, (match, separator, chr) => chr ? chr.toUpperCase() : '')
      .replace(STRING_CAMELIZE_REGEXP_2, (match, separator, chr) => match.toLowerCase());
  }
docs: Returns the lowerCamelCase form of a string.
  ```javascript
  'innerHTML'.camelize();          // 'innerHTML'
  'action_name'.camelize();        // 'actionName'
  'css-class-name'.camelize();     // 'cssClassName'
  'my favorite items'.camelize();  // 'myFavoriteItems'
  'My Favorite Items'.camelize();  // 'myFavoriteItems'
  'private-docs/owner-invoice'.camelize(); // 'privateDocs/ownerInvoice'
  ```
  @method camelize
  @param {String} str The string to camelize.
  @return {String} the camelized string.