Custom script action based on user

ERPNext Customize ERPNext
1

I’m using ERPNext for 2 companies in the system.
I would like for a specific employee to select the other company by default.
I can do it with custom script but I’m missing the part to detect which user opened a new sales order or sales invoice.

Here is my custom script code.
I want to add something like if the user id is X execute the code).

frappe.ui.form.on(“Sales Order”, “onload”, function(frm) {
frm.set_value(“company”,“My 2nd company”)
});

Thanks