minify-html/src/minify/esbuild.rs

#[cfg(feature = "js-esbuild")]
use {aho_corasick::AhoCorasick, crossbeam::sync::WaitGroup, esbuild_rs::TransformOptions};

#[cfg(feature = "js-esbuild")]
// TODO The use of WG is ugly and we don't want to be multi-threaded; wait for Rust port esbuild-transform-rs.
// `tag_to_escape` must be case insensitive if provided.
pub fn minify_using_esbuild(
    out: &mut Vec<u8>,
    code: &[u8],
    transform_options: &TransformOptions,
    tag_to_escape: Option<&'static AhoCorasick>,
) {
    let wg = WaitGroup::new();
    unsafe {
        let wg = wg.clone();
        esbuild_rs::transform_direct_unmanaged(code, transform_options, move |result| {
            let min_code = result.code.as_str().trim().as_bytes();
            match tag_to_escape {
                None => out.extend_from_slice(min_code),
                // TODO (JS) Handle other forms:
                // 1 < /script/.exec(a).length
                // `  ${`  ${a</script/}  `}  `
                // // </script>
                // /* </script>
                // Considerations:
                // - Need to parse strings (e.g. "", '', ``) so syntax within strings aren't mistakenly interpreted as code.
                // - Need to be able to parse regex literals to determine string delimiters aren't actually characters in the regex.
                // - Determining whether a slash is division or regex requires a full-blown JS parser to handle all cases (this is a well-known JS parsing problem).
                // - `/</script` or `/</ script` are not valid JS so don't need to be handled.
                // TODO (CSS) Are there other places that can have unintentional closing tags?
                Some(tag_to_escape) => {
                    tag_to_escape.replace_all_with_bytes(min_code, out, |_, orig, dst| {
                        dst.extend(b"<\\/");
                        // Keep original case.
                        dst.extend(&orig[2..]);
                        true
                    })
                }
            }
            drop(wg);
        });
    };
    wg.wait();
}