Pass Data into another Doctype

Hi
I have a Doctype Customer in which i want to fetch data into it from the Opportunity.

below custom script work for version 10 but not worked in version 11.


var prev_route = frappe.get_prev_route();
console.log(prev_route);
if(prev_route[1] == “Opportunity”) {
prev_route_details = prev_route;
set_default_values();
}

any help?