in packages/fbjs/src/core/CSSCore.js [65:83]
removeClass: function(element, className) {
invariant(
!/\s/.test(className),
'CSSCore.removeClass takes only a single class name. "%s" contains ' +
'multiple classes.', className
);
if (className) {
if (element.classList) {
element.classList.remove(className);
} else if (CSSCore.hasClass(element, className)) {
element.className = element.className
.replace(new RegExp('(^|\\s)' + className + '(?:\\s|$)', 'g'), '$1')
.replace(/\s+/g, ' ') // multiple spaces to one
.replace(/^\s*|\s*$/g, ''); // trim the ends
}
}
return element;
},