fix(fm): fix frontmatter formatting

crates/rari-doc/Cargo.toml

@@ -19,6 +19,8 @@ indexmap.workspace = true
 
 serde_yaml_ng = "0.10"
 yaml-rust = "0.4"
+pretty_yaml = "0.5"
+yaml_parser = "0.2"
 percent-encoding = "2"
 pest = "2"
 pest_derive = "2"

crates/rari-doc/src/error.rs

@@ -45,6 +45,8 @@ pub enum DocError {
     NoFrontmatter,
     #[error("Invalid frontmatter: {0}")]
     InvalidFrontmatter(#[from] serde_yaml_ng::Error),
+    #[error("Invalid frontmatter to format: {0}")]
+    InvalidFrontmatterToFmt(#[from] yaml_parser::SyntaxError),
     #[error(transparent)]
     EnvError(#[from] EnvError),
     #[error(transparent)]

crates/rari-doc/src/pages/types/doc.rs

@@ -4,6 +4,7 @@ use std::io::{BufWriter, Write};
 use std::path::{Path, PathBuf};
 use std::sync::Arc;
 
+use pretty_yaml::config::{FormatOptions, LanguageOptions};
 use rari_md::m2h;
 use rari_types::fm_types::{FeatureStatus, PageType};
 use rari_types::locale::Locale;
@@ -341,17 +342,34 @@ fn write_doc(doc: &Doc) -> Result<(), DocError> {
     if let Some(parent) = file_path.parent() {
         std::fs::create_dir_all(parent)?;
     }
+    let fm_str = fm_to_string(&frontmatter)?;
+
     let file = fs::File::create(&file_path)?;
     let mut buffer = BufWriter::new(file);
     buffer.write_all(b"---\n")?;
-    serde_yaml_ng::to_writer(&mut buffer, &frontmatter)?;
+    buffer.write_all(fm_str.as_bytes())?;
     buffer.write_all(b"---\n")?;
 
     buffer.write_all(doc.raw[content_start..].as_bytes())?;
 
     Ok(())
 }
 
+fn fm_to_string(fm: &FrontMatter) -> Result<String, DocError> {
+    let fm_str = serde_yaml_ng::to_string(fm)?;
+    Ok(pretty_yaml::format_text(
+        &fm_str,
+        &FormatOptions {
+            language: LanguageOptions {
+                quotes: pretty_yaml::config::Quotes::PreferDouble,
+                indent_block_sequence_in_map: true,
+                ..Default::default()
+            },
+            ..Default::default()
+        },
+    )?)
+}
+
 pub fn render_md_to_html(input: &str, locale: Locale) -> Result<String, DocError> {
     let html = m2h(input, locale)?;
     Ok(html)
@@ -397,7 +415,7 @@ mod tests {
         let meta = serde_yaml_ng::from_str::<FrontMatter>(fm).unwrap();
         assert_eq!(meta.browser_compat.len(), 2);
 
-        assert_eq!(fm, serde_yaml_ng::to_string(&meta).unwrap());
+        assert_eq!(fm, fm_to_string(&meta).unwrap());
 
         let fm = r#"
         browser-compat: foo