Recently We got a client who came to us with this error, Client did not know that error. Her website was built with Woocommerce front end manager and foo events. When they tried to create event product from front end, additional option was not showing. We checked the browser console find out this “Uncaught Reference Error: wp is not defined“.
There are many reasons for this. Most people say on stackoverflow and wordpress forum that it is due to cache plugin or js optimization plugin.
But our client was not using any cache plugin. The site was built with divi and divi has performance optimization. We disabled that. Then we logged in to her web hosting and disabled varnish cache. But the issue still remained.
For us it was a plugin conflict, we have to find out that plugin disabled that conflicting code to fix this error.