FIX francoismassart#83

Author: francoismassart

lib/util/attr.js

@@ -32,7 +32,8 @@ function isSingleLine(str) {
  */
 function getClassNamesFromAttribute(attrVal, trim = true) {
   let classNames = [];
-  if (attrVal === undefined || attrVal === null || attrVal.length === 0) {
+  const valid = typeof attrVal === 'string' && attrVal.length;
+  if (!valid) {
     return classNames;
   }
   if (isSingleLine(attrVal)) {

tests/lib/rules/no-custom-classname.js

@@ -496,6 +496,16 @@ ruleTester.run("no-custom-classname", rule, {
       code: `
       <div className={'!hidden sm:!flex lg:!block 2xl:!block'}>Important modifier</div>`,
     },
+    {
+      code: `
+      <button
+      type="button"
+      className={classnames(
+        "p-2 font-medium",
+        boolVal ? false : "text-black"
+      )}
+      />`,
+    },
   ],
 
   invalid: [