Dynamically modify a form field property in frappe

If you ever need to provide dynamic updates to a form field in the frappe framework, here's how you do it.

Let's say we want to give the user a dynamic update on the length of the string in a text box. In a client-side javascript event function we could write:

frm.set_df_property("text", "description", `${frm.doc.text.length}/280`);
frm.refresh_field("text");
// optional:
frm.trigger("run_some_other_function");

Where text is the field name, description is the property and ${frm.doc.text.length}/280 is the content you want to assign to the property.