Added magic comment visitor and wired it up to the transformer

crates/atlaspack_plugin_transformer_js/src/js_transformer/conversion.rs

@@ -3,6 +3,7 @@ use std::sync::Arc;
 
 use atlaspack_core::diagnostic;
 use indexmap::IndexMap;
+use std::collections::HashMap;
 use swc_core::atoms::{Atom, JsWord};
 
 use atlaspack_core::plugin::{PluginOptions, TransformResult};
@@ -44,6 +45,7 @@ pub(crate) fn convert_result(
     &options.project_root,
     transformer_config,
     result.dependencies,
+    result.magic_comments,
     &asset,
   )?;
 
@@ -381,6 +383,7 @@ pub(crate) fn convert_dependencies(
   project_root: &Path,
   transformer_config: &atlaspack_js_swc_core::Config,
   dependencies: Vec<atlaspack_js_swc_core::DependencyDescriptor>,
+  magic_comments: HashMap<String, String>,
   asset: &Asset,
 ) -> Result<(IndexMap<Atom, Dependency>, Vec<PathBuf>), Vec<Diagnostic>> {
   let mut dependency_by_specifier = IndexMap::new();
@@ -400,7 +403,13 @@ pub(crate) fn convert_dependencies(
     )?;
 
     match result {
-      DependencyConversionResult::Dependency(dependency) => {
+      DependencyConversionResult::Dependency(mut dependency) => {
+        if let Some(chunk_name) = magic_comments.get(&dependency.specifier) {
+          dependency.meta.insert(
+            "chunkNameMagicComment".to_string(),
+            chunk_name.clone().into(),
+          );
+        }
         dependency_by_specifier.insert(placeholder, dependency);
       }
       DependencyConversionResult::InvalidateOnFileChange(file_path) => {

packages/transformers/js/core/Cargo.toml

@@ -47,5 +47,6 @@ atlaspack_contextual_imports = { path = "../../../../crates/atlaspack_contextual
 atlaspack_swc_runner = { path = "../../../../crates/atlaspack_swc_runner" }
 parking_lot = { workspace = true }
 regex = { workspace = true }
+anyhow = { workspace = true }
 tracing = { workspace = true }
 tracing-test = { workspace = true }

packages/transformers/js/core/src/lib.rs

@@ -5,6 +5,7 @@ mod env_replacer;
 mod fs;
 mod global_replacer;
 mod hoist;
+mod magic_comments;
 mod modules;
 mod node_replacer;
 pub mod test_utils;
@@ -39,6 +40,7 @@ pub use hoist::ExportedSymbol;
 use hoist::HoistResult;
 pub use hoist::ImportedSymbol;
 use indexmap::IndexMap;
+use magic_comments::MagicCommentsVisitor;
 use modules::esm2cjs;
 use node_replacer::NodeReplacer;
 use path_slash::PathExt;
@@ -152,6 +154,7 @@ pub struct TransformResult {
   pub has_node_replacements: bool,
   pub is_constant_module: bool,
   pub conditions: HashSet<Condition>,
+  pub magic_comments: HashMap<String, String>,
 }
 
 fn targets_to_versions(targets: &Option<HashMap<String, String>>) -> Option<Versions> {
@@ -266,6 +269,13 @@ pub fn transform(
 
               let global_mark = Mark::fresh(Mark::root());
               let unresolved_mark = Mark::fresh(Mark::root());
+
+              if code.contains("webpackChunkName") {
+                let mut magic_comment_visitor = MagicCommentsVisitor::new(code);
+                module.visit_with(&mut magic_comment_visitor);
+                result.magic_comments = magic_comment_visitor.magic_comments;
+              }
+
               let module = module.fold_with(&mut chain!(
                 resolver(unresolved_mark, global_mark, config.is_type_script),
                 // Decorators can use type information, so must run before the TypeScript pass.

packages/transformers/js/core/src/magic_comments/mod.rs

@@ -0,0 +1,5 @@
+mod visitor;
+#[cfg(test)]
+mod visitor_test;
+
+pub use self::visitor::*;

packages/transformers/js/core/src/magic_comments/visitor.rs

@@ -0,0 +1,71 @@
+use std::collections::HashMap;
+use std::rc::Rc;
+
+use regex::Regex;
+use swc_core::common::Span;
+use swc_core::ecma::ast::*;
+use swc_core::ecma::utils::ExprExt;
+use swc_core::ecma::visit::{Visit, VisitWith};
+
+thread_local! {
+  static RE_CHUNK_NAME: Rc<Regex> = Rc::new(Regex::new(r#"webpackChunkName:\s*['"](?<name>[^'"]+)['"]"#).unwrap());
+}
+
+#[derive(Debug)]
+pub struct MagicCommentsVisitor<'a> {
+  pub magic_comments: HashMap<String, String>,
+  pub offset: u32,
+  pub code: &'a str,
+}
+
+impl<'a> MagicCommentsVisitor<'a> {
+  pub fn new(code: &'a str) -> Self {
+    Self {
+      magic_comments: Default::default(),
+      offset: 0,
+      code,
+    }
+  }
+
+  fn fix_callee(&self, span: &Span) -> (u32, u32) {
+    let start = span.lo().0 - self.offset;
+    let end = span.hi().0 - self.offset;
+    (start, end)
+  }
+}
+
+impl<'a> Visit for MagicCommentsVisitor<'a> {
+  fn visit_module(&mut self, node: &Module) {
+    self.offset = node.span.lo().0;
+    node.visit_children_with(self);
+  }
+
+  fn visit_call_expr(&mut self, node: &CallExpr) {
+    if !node.callee.is_import() || node.args.len() == 0 || !node.args[0].expr.is_str() {
+      node.visit_children_with(self);
+      return;
+    }
+
+    let code_start_index = (code_start - 1) as usize;
+    let code_end_index = (code_end - 1) as usize;
+    let inner = &self.code[code_start_index..code_end_index];
+
+    let re = RE_CHUNK_NAME.with(|re| re.clone());
+
+    let Some(caps) = re.captures(inner) else {
+      return;
+    };
+
+    let Some(found) = caps.name("name") else {
+      return;
+    };
+
+    let Expr::Lit(Lit::Str(specifier)) = &*node.args[0].expr else {
+      return;
+    };
+
+    self
+      .magic_comments
+      .insert(specifier.value.to_string(), found.as_str().to_string());
+  }
+}