Function prettify_js::maybe_prettyprint

pub fn maybe_prettyprint<G>(
    script_name: &str, 
    source_str: &mut String, 
    generate_file: G
) where
    G: FnMut(String, String) -> String, 

Convenience function to create a sourcemap for the prettyprinted version of the file (if it needs prettyprinting), generate a URL for it and append that URL to the file text so it gets used.

The generate_file closure takes a file name and file text and returns a URL which can be used to load that file. This URL is injected into source_str.

Example:

let mut generated = "//PRETTYPRINT\nfunction x(a){return a;}".to_string();
prettify_js::maybe_prettyprint("demo.js", &mut generated,
  |name, text| {
    assert_eq!(name, "demo.js.sourcemap");
    let url = "https://example.com/demo.js.sourcemap".to_string();
    println!("Serve {} with contents {}", &url, text);
    url
  });
assert_eq!(generated, "//PRETTYPRINT\nfunction x(a){return a;}\n//# sourceMappingURL=https://example.com/demo.js.sourcemap");