filterElements doesn't work

[mj4444]

I want to exclude some DOM elements based on some class.
For this I used filterElements:-

findAndReplaceDOMText(container, {
    filterElements: function(el) {
       if (el.className) {
            return el.className.indexOf('test') === -1;
        }
    },
    find: regex,
    replace: function(portion, match) {
        called = true;
        var el = document.createElement('span');
        el.className = 'custom_highlight';
        el.innerHTML = portion.text;
        return el;
    },
});