feat: add compact html (#8)

Author: Princesseuh

crates/astro_codegen/src/lib.rs

@@ -25,7 +25,7 @@ mod printer;
 pub mod scanner;
 
 pub use diagnostic::{Diagnostic, DiagnosticLabel, DiagnosticSeverity};
-pub use options::{ScopedStyleStrategy, SourcemapOption, TransformOptions};
+pub use options::{CompactMode, ScopedStyleStrategy, SourcemapOption, TransformOptions};
 pub use printer::{
     AstroCodegen, HoistedScriptType, StyleBlock, TransformResult, TransformResultHoistedScript,
     TransformResultHydratedComponent, extract_styles, transform,

crates/astro_codegen/src/options.rs

@@ -1,6 +1,6 @@
 //! Options for Astro codegen.
 //!
-//! Some fields (such as `compact`, `sourcemap`, CSS scoping) are accepted but
+//! Some fields (such as `sourcemap`, CSS scoping) are accepted but
 //! stubbed for API compatibility.
 
 /// Controls whether and how source maps are emitted.
@@ -25,6 +25,26 @@ impl SourcemapOption {
     }
 }
 
+/// Controls how whitespace is collapsed in the HTML output.
+///
+/// - `Disabled` (default): no whitespace modification.
+/// - `Html`: HTML-aware whitespace collapsing, following the same rules as a browser
+///   (preserves significant whitespace, collapses runs of whitespace to a single
+///   space or newline, removes whitespace-only text nodes in insensitive contexts).
+///   Matches the Go compiler's `compact: true` behavior.
+/// - `Jsx`: removes all whitespace-only text nodes and strips leading/trailing
+///   whitespace from text content. Similar to how JSX transformers handle whitespace.
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Default)]
+pub enum CompactMode {
+    /// No whitespace modification (default).
+    #[default]
+    Disabled,
+    /// HTML-aware whitespace collapsing (Go compiler `compact: true` behavior).
+    Html,
+    /// Strip all whitespace-only text nodes and leading/trailing whitespace.
+    Jsx,
+}
+
 /// Scoped style strategy for CSS scoping.
 ///
 /// Determines how Astro scopes CSS selectors to components.
@@ -66,11 +86,12 @@ pub struct TransformOptions {
     /// Defaults to `"https://astro.build"`.
     pub astro_global_args: Option<String>,
 
-    /// Whether to collapse whitespace in the HTML output.
+    /// Controls how whitespace is collapsed in the HTML output.
     ///
-    /// **Stub**: compact mode is not yet implemented; this field is accepted
-    /// for API compatibility.
-    pub compact: bool,
+    /// - `Disabled` (default): no whitespace modification.
+    /// - `Html`: HTML-aware collapsing following browser whitespace rules.
+    /// - `Jsx`: strip all whitespace-only text nodes and leading/trailing whitespace.
+    pub compact: CompactMode,
 
     /// Enable scoped slot result handling.
     ///
@@ -149,7 +170,7 @@ impl Default for TransformOptions {
             internal_url: None,
             sourcemap: SourcemapOption::default(),
             astro_global_args: None,
-            compact: false,
+            compact: CompactMode::Disabled,
             result_scoped_slot: false,
             scoped_style_strategy: ScopedStyleStrategy::default(),
             transitions_animation_url: None,
@@ -226,9 +247,13 @@ impl TransformOptions {
         self
     }
 
-    /// Enable or disable compact mode (stub).
+    /// Set the compact whitespace collapsing mode.
+    ///
+    /// - `CompactMode::Disabled`: no whitespace modification (default).
+    /// - `CompactMode::Html`: HTML-aware collapsing (Go compiler behavior).
+    /// - `CompactMode::Jsx`: strip all whitespace-only text nodes.
     #[must_use]
-    pub fn with_compact(mut self, compact: bool) -> Self {
+    pub fn with_compact(mut self, compact: CompactMode) -> Self {
         self.compact = compact;
         self
     }

crates/astro_codegen/src/printer/components.rs

@@ -9,8 +9,9 @@ use super::elements::ScopeId;
 use super::escape::{decode_html_entities, escape_double_quotes};
 use super::expr_to_string;
 use super::runtime;
+use super::whitespace::has_is_raw_attr;
 use crate::css_scoping;
-use crate::options::ScopedStyleStrategy;
+use crate::options::{CompactMode, ScopedStyleStrategy};
 use crate::scanner::{get_jsx_attribute_name, is_custom_element};
 use oxc_ast::ast::*;
 
@@ -102,6 +103,14 @@ impl<'a> AstroCodegen<'a> {
         // Check if this is a custom element (has dash in name)
         let is_custom = is_custom_element(name);
 
+        // Track raw element depth for compact whitespace collapsing.
+        // A component with `is:raw` has its slot children treated as raw text.
+        let is_raw = self.options.compact != CompactMode::Disabled
+            && has_is_raw_attr(&el.opening_element.attributes);
+        if is_raw {
+            self.raw_element_depth += 1;
+        }
+
         // Check for server:defer directive
         let mut server_defer_info = if Self::has_server_defer(&el.opening_element.attributes) {
             Some(ServerDeferInfo {
@@ -270,6 +279,10 @@ impl<'a> AstroCodegen<'a> {
             self.add_source_mapping_for_span(closing.span);
         }
         self.print(")}");
+
+        if is_raw {
+            self.raw_element_depth -= 1;
+        }
     }
 
     /// Extract `set:html` or `set:text` value from component attributes.

crates/astro_codegen/src/printer/elements.rs

@@ -8,9 +8,10 @@
 
 use super::escape::{escape_double_quotes, escape_html_attribute};
 use super::runtime;
+use super::whitespace::{has_is_raw_attr, is_raw_element_name};
 use super::{AstroCodegen, expr_to_string};
 use crate::css_scoping;
-use crate::options::ScopedStyleStrategy;
+use crate::options::{CompactMode, ScopedStyleStrategy};
 use crate::scanner::get_jsx_attribute_name;
 use oxc_ast::ast::*;
 
@@ -114,6 +115,15 @@ impl<'a> AstroCodegen<'a> {
             self.has_explicit_head = true;
         }
 
+        // Track raw element depth for compact whitespace collapsing.
+        // Raw elements are those whose text content must never be modified:
+        // <pre>, <textarea>, <script>, <style>, etc., and any element with `is:raw`.
+        let is_raw = self.options.compact != CompactMode::Disabled
+            && (is_raw_element_name(name) || has_is_raw_attr(&el.opening_element.attributes));
+        if is_raw {
+            self.raw_element_depth += 1;
+        }
+
         // Insert $$maybeRenderHead before the first body HTML element
         self.maybe_insert_render_head(name);
 
@@ -150,10 +160,8 @@ impl<'a> AstroCodegen<'a> {
 
         // Handle special head insertion
         if is_head {
-            // Children
-            for child in &el.children {
-                self.print_jsx_child(child);
-            }
+            // Children (use compact-aware printing)
+            self.print_jsx_children_compact(&el.children);
             // Insert renderHead before closing head tag
             self.print(&format!(
                 "${{{}({})}}",
@@ -178,10 +186,8 @@ impl<'a> AstroCodegen<'a> {
                 self.print(&format!("${{{value}}}"));
             }
         } else {
-            // Regular children
-            for child in &el.children {
-                self.print_jsx_child(child);
-            }
+            // Regular children with compact-aware printing
+            self.print_jsx_children_compact(&el.children);
         }
 
         // Closing tag (skip for void elements like <meta>, <input>, <br>, etc.)
@@ -195,6 +201,9 @@ impl<'a> AstroCodegen<'a> {
             self.print(">");
         }
 
+        if is_raw {
+            self.raw_element_depth -= 1;
+        }
         if is_head {
             self.in_head = was_in_head;
         }

crates/astro_codegen/src/printer/expressions.rs

@@ -27,9 +27,7 @@ impl<'a> AstroCodegen<'a> {
         self.print(&format!(",{{}},{{\"default\": {async_prefix}{slot_params}"));
         self.print(runtime::RENDER);
         self.print("`");
-        for child in &frag.children {
-            self.print_jsx_child(child);
-        }
+        self.print_jsx_children_compact(&frag.children);
         // Map the closing fragment tag (</>) to the `)` that closes
         // $$renderComponent(...) — the semantic equivalent in generated code.
         if !frag.closing_fragment.span.is_empty() {
@@ -118,9 +116,7 @@ impl<'a> AstroCodegen<'a> {
                     ));
                     self.print(runtime::RENDER);
                     self.print("`");
-                    for child in &frag.children {
-                        self.print_jsx_child(child);
-                    }
+                    self.print_jsx_children_compact(&frag.children);
                     // Map closing fragment tag (</>) before the closing boilerplate.
                     if !frag.closing_fragment.span.is_empty() {
                         self.add_source_mapping_for_span(frag.closing_fragment.span);
@@ -130,9 +126,7 @@ impl<'a> AstroCodegen<'a> {
                     // Implicit fragments (multiple JSX siblings) are just wrapped in $$render`...`
                     self.print(runtime::RENDER);
                     self.print("`");
-                    for child in &frag.children {
-                        self.print_jsx_child(child);
-                    }
+                    self.print_jsx_children_compact(&frag.children);
                     self.print("`");
                 }
             }