How to modify a page footer from a show rule?

[vestal dragon]

I'm writing a template and I want to add the page number for pages with custom footers

?render ```typ
#set page(number-align: right, numbering: "1")
#show page: p => {
if not p.has("footer") { p }
p.footer = {
p.footer
align(right, align(right, counter(page).display("1", both: false)))
}
};
#page(
footer: lorem(20),
lorem(300)
)
#page(
lorem(300)
)

[twilit jasper]

An error occurred:

Error: expected dictionary, found content
    ╭─[<user input>:11:3]
    │
 11 │   p.footer = {
    │   ─  
    │       
────╯

[vestal dragon]

?render ```typ
#set page(number-align: right, numbering: "1")
#show page: p => {
if not p.has("footer") { p }
p.at("footer") = {
p.footer
align(right, align(right, counter(page).display("1", both: false)))
}
};
#page(
footer: lorem(20),
lorem(300)
)
#page(
lorem(300)
)

[twilit jasper]

An error occurred:

Error: type content has no method `at`
    ╭─[<user input>:11:3]
    │
 11 │   p.at("footer") = {
    │   ──────────────  
    │                    
────╯

[vestal dragon]

?render ```typ
#set page(number-align: right, numbering: "1")
#show page: p => {
if not p.has("footer") {
return p;
}
set page(footer: {
p.footer
align(right, counter(page).display("1", both: false))
});
p
};
#page(
footer: lorem(20),
lorem(300)
)
#page(
lorem(300)
)

[twilit jasper]

Note: 1 more page ignored

[fiery fiber]

?render pagesize=default

#set page(number-align: right, numbering: "1")
#show page: p => {
  if not p.has("footer") {
    return p;
  }
  set page(footer: {
    p.footer
    align(right, counter(page).display("1", both: false))
  });
  p
};
#page(
  footer: lorem(20),
  lorem(300)
)
#page(
  lorem(300)
)