Error when have a class attribute for optgroup tag

[walid-ajaj]

bootstrap-select/js/bootstrap-select.js

Line 731 in 939e94b

if (typeof classes !== 'undefined' && classes !== '') a.classList.add.apply(a.classList, classes.split(/\s+/));

Browser will throw the error exception DOMException: Failed to execute 'add' on 'DOMTokenList': The token provided must not be empty. when you have <optgroup /> with a value in class attribute.

Example: https://jsfiddle.net/9jbr5h0u/

<select class="selectpicker show-menu-arrow" data-live-search="true" title="Choose one of the following..." data-size="10" >
  <option>-- Select --</option>
  <optgroup label="Test Group" class="test-style">
    <option>Honda</option>
    <option>Civic</option>
    <option>Accord</option>
    <option>Odyssey</option>
  </optgroup>
</select>

The issue is:
in line 1684 plugin try to add class name opt followed with a space.
However, in line 1732 config.optgroupClass is already have a space followed with value <optgroup /> have a class attribute.
This lead optionClass in line 1684 to have two class names separated with two spaces.

Now in line 731 the code classes.split() will create a an array which second element is an empty string, and that empty string element is the one cause the Exception when browser try to add it as class name.

My quick fix for this issue is to filter the result array and remove the empty elements:
if (typeof classes !== 'undefined' && classes !== '') a.classList.add.apply(a.classList, classes.split(/\s+/).filter(function(x) {return x!==''}));

Not sure if there is other places could have same bug, but same fix cam be applied to eveywhere there is a split() call:

bootstrap-select/js/bootstrap-select.js

Line 731 in 939e94b

if (typeof classes !== 'undefined' && classes !== '') a.classList.add.apply(a.classList, classes.split(/\s+/));

bootstrap-select/js/bootstrap-select.js

Line 2069 in 939e94b

if (buttonClass) button.classList.add.apply(button.classList, buttonClass.split(' '));

bootstrap-select/js/bootstrap-select.js

Line 2071 in 939e94b

if (buttonClass) button.classList.remove.apply(button.classList, buttonClass.split(' '));

bootstrap-select/js/bootstrap-select.js

Line 2073 in 939e94b

if (style) button.classList.remove.apply(button.classList, style.split(' '));

bootstrap-select/js/bootstrap-select.js

Line 2074 in 939e94b

if (buttonClass) button.classList.add.apply(button.classList, buttonClass.split(' '));

Regards,