Failed to execute 'add' on 'DOMTokenList'

[ajorias]

Vue.js v1.0.21
vue-router v0.7.13

<cc-page class=""></cc-page>

Leads to

"Uncaught SyntaxError: Failed to execute 'add' on 'DOMTokenList': The token provided must not be empty." in Chrome Version 49.0.2623.112 m

In the function

/**
 * Add class with compatibility for IE & SVG
 *
 * @param {Element} el
 * @param {String} cls
 */

function addClass(el, cls) {
    if (el.classList) {
        el.classList.add(cls);
    } else {
        var cur = ' ' + getClass(el) + ' ';
        if (cur.indexOf(' ' + cls + ' ') < 0) {
            setClass(el, (cur + cls).trim());
        }
    }
}

Because parameter 'cls' is an empty string in this case and the error happens in my case in

el.classList.add(cls);

Maybe an empty 'cls' should lead to an early out here.

[icemanjin]

thanks