ERPNext: automatically set Tax Category in Address DocType

address.js

// Client Script
frappe.ui.form.on("Address", {
    refresh(frm) {
        frm.trigger("set_tax_category");
    },
    country(frm) {
        frm.trigger("set_tax_category");
    },
    links(frm) {
        frm.trigger("set_tax_category");
    },
    set_tax_category (frm) {
        if (frm.doc.tax_category || frm.doc.country !== "Germany") return;

        const links = frm.doc.links.map(row => row.link_doctype);
        if (links.includes("Customer")) {
            frm.set_value("tax_category", "Umsatzsteuer");
        } else if (links.includes("Supplier")) {
            frm.set_value("tax_category", "Vorsteuer");
        }
    }
});