Add support or user error when using with mkdocs-material's instant loading

[timvink]

mkdocs-material theme offers an experimental feature called instant loading.

When enabled, navigating to the print site page does not work properly.

Todo, investigate and either:

• raise a user error to explain the incompability (and suggest to either disable this plugin, or turn off instant loading)
• Somehow fix the issue :)

[timvink]

From squidfunk/mkdocs-material#1918 I learned you can to support instant loading by subscribing to the app:

if (
  typeof app !== "undefined" && 
  typeof app.document$ !== "undefined"
) {
  app.document$.subscribe(function() {
    // custom logic
  })
}

In this plugin however, I only inject javascript into one specific page, the print site page. It should not run anywhere else.

What I could do, is detect the page and only execute the JS there.

window.location.pathname Returns:

• "/print_page.html" (without directory urls, mkdocs serve)
• "/print_page" (with directory urls, mkdocs serve)
• (mkdocs build)

That won't work. Instead, I could add a classname to the print site page, and only execute the JS if it's in the body, as suggested here: https://stackoverflow.com/a/9578898/5525118.

I would then need to add the javascript files (with the functions only) to all mkdocs pages, and add to all pages a bit of js that only on the print page calls the appropriate functions (depending on plugin config settings).

Because I'll be calling js functions now, I should simplify and just make a single print-site.js file with all functions.

[timvink]

Fixed in 2260505