Structural replace ES5 prototype to ES6 class

Apologies if this belongs in WebStorm, I use IntelliJ IDEA so posting here.

I am trying to convert something like this to a ES6 class

function ClassName(param1, param2) {
//statements
}

ClassName.prototype.methodName = function() {
//statements
};

This is as far as I got -

I can't figure out how to match the constructor plus all the following prototype methods and replace it all in one shot. The above template also seems to be buggy (or I am doing something wrong), some methods are missing their return keyword and some have additional braces inside the method body.