rolldown 1.0.0

Fast JavaScript bundler in Rust, designed for the future of Vite
Documentation
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
use oxc::ast::ast::Str;
use oxc::{
  allocator::{Allocator, Box as ArenaBox, IntoIn, TakeIn},
  ast::{
    AstBuilder, NONE,
    ast::{self, ExportDefaultDeclarationKind, Expression, ObjectPropertyKind, Statement},
  },
  semantic::{IsGlobalReference, Scoping, SymbolId},
  span::{SPAN, Span},
};

use rolldown_common::{
  ExternalModule, ImportRecordIdx, ImportRecordMeta, IndexModules, Module, ModuleIdx, NormalModule,
};
use rolldown_ecmascript::CJS_REQUIRE_REF_STR;
use rolldown_ecmascript_utils::{AstSnippet, ExpressionExt};
use rolldown_utils::{
  ecmascript::is_validate_identifier_name,
  indexmap::{FxIndexMap, FxIndexSet},
};
use rustc_hash::{FxHashMap, FxHashSet};

use crate::hmr::utils::{HmrAstBuilder, MODULE_EXPORTS_NAME_FOR_ESM};

pub struct HmrAstFinalizer<'me, 'ast> {
  // Outside input
  pub alloc: &'ast Allocator,
  pub snippet: AstSnippet<'ast>,
  pub builder: &'me AstBuilder<'ast>,
  pub modules: &'me IndexModules,
  pub module: &'me NormalModule,
  pub affected_module_idx_to_init_fn_name: &'me FxHashMap<ModuleIdx, String>,
  pub use_pife_for_module_wrappers: bool,

  /// Whether the runtime should short-circuit re-execution of the wrapped module body
  /// when its stable id is already registered.
  ///
  /// `true` for lazy-compilation chunks: when a module appears in two lazy bundles served
  /// concurrently, we want only the first one to actually execute the body.
  ///
  /// `false` for HMR patches: the patch's whole point is to re-execute the body and
  /// replace the registered exports, so deduping would silently drop the update.
  ///
  /// Note: This works only as a **workaround**. In the future, HMR runtime should
  /// provide a runtime API to trigger module disposal and re-execution. @hana
  pub dedup_module_initializer: bool,

  // Each module has a unique index, which is used to generate something that needs to be unique.
  pub unique_index: usize,

  // --- Internal state
  /// For
  ///
  /// ```js
  /// import foo, { bar } from './foo.js';
  /// ```
  ///
  /// , assuming `foo` and `bar` have symbol id `1` and `2`, we will store mapping like:
  ///
  /// - 1 => "import_foo_1.default"
  /// - 2 => "import_foo_1.bar"
  ///
  /// `import_foo_1` is the binding name we gonna used to generate code like
  ///
  /// ```js
  /// const import_foo_1 = __rolldown_runtime__.loadExports('./foo.js');
  /// ```
  pub import_bindings: FxHashMap<SymbolId, String>,
  pub exports: oxc::allocator::Vec<'ast, ObjectPropertyKind<'ast>>,
  pub re_export_all_dependencies: FxIndexSet<ModuleIdx>,
  pub dependencies: FxIndexSet<ModuleIdx>,
  pub imports: FxHashSet<ModuleIdx>,
  pub generated_static_import_infos: FxHashMap<ModuleIdx, String>,
  // We need to store the static import statements for external separately, so we could put them outside of the `try` block.
  pub generated_static_import_stmts_from_external: FxIndexMap<ModuleIdx, ast::Statement<'ast>>,
  pub named_exports: FxHashMap<Str<'ast>, NamedExport>,
}

impl<'ast> HmrAstFinalizer<'_, 'ast> {
  #[expect(clippy::too_many_lines)]
  pub fn handle_top_level_stmt(
    &mut self,
    program_body: &mut oxc::allocator::Vec<'ast, ast::Statement<'ast>>,
    mut node: ast::Statement<'ast>,
    scoping: &Scoping,
  ) {
    match node {
      ref mut module_decl @ ast::match_module_declaration!(Statement) => {
        let module_decl = module_decl.to_module_declaration_mut();

        match module_decl {
          ast::ModuleDeclaration::ImportDeclaration(import_decl) => {
            // Transform
            // ```js
            // import foo, { bar } from './foo.js';
            // console.log(foo, bar);
            // ```
            // to
            // ```js
            // const import_foo = __rolldown_runtime__.loadExports('./foo.js');
            // console.log(import_foo.default, import_foo.bar);
            // ```
            let rec_id = self.module.imports[&import_decl.span];
            let rec = &self.module.import_records[rec_id];
            let Some(importee_idx) = rec.resolved_module else { return };
            let importee = &self.modules[importee_idx];
            self.dependencies.insert(importee_idx);
            let binding_name = self.ensure_static_import_info(importee_idx, rec_id).to_string();
            import_decl.specifiers.as_ref().inspect(|specifiers| {
              specifiers.iter().for_each(|spec| match spec {
                ast::ImportDeclarationSpecifier::ImportSpecifier(import_specifier) => {
                  self.import_bindings.insert(
                    import_specifier.local.symbol_id(),
                    format!("{binding_name}.{}", import_specifier.imported.name()),
                  );
                }
                ast::ImportDeclarationSpecifier::ImportDefaultSpecifier(
                  import_default_specifier,
                ) => {
                  self.import_bindings.insert(
                    import_default_specifier.local.symbol_id(),
                    format!("{binding_name}.default"),
                  );
                }
                ast::ImportDeclarationSpecifier::ImportNamespaceSpecifier(
                  import_namespace_specifier,
                ) => {
                  self
                    .import_bindings
                    .insert(import_namespace_specifier.local.symbol_id(), binding_name.clone());
                }
              });
            });
            match importee {
              Module::Normal(_) => {
                if let Some(stmt) =
                  self.create_load_exports_call_stmt(importee, &binding_name, import_decl.span)
                {
                  program_body.push(stmt);
                }
              }
              Module::External(importee_ext) => {
                self.create_static_import_stmt_from_external_module(
                  importee_ext,
                  &binding_name,
                  import_decl.span,
                );
              }
            }
          }
          ast::ModuleDeclaration::ExportNamedDeclaration(decl) => {
            if let Some(_source) = &decl.source {
              // export {} from '...'
              let rec_id = self.module.imports[&decl.span];
              let rec = &self.module.import_records[rec_id];
              let Some(importee_idx) = rec.resolved_module else { return };
              let importee = &self.modules[importee_idx];
              self.dependencies.insert(importee_idx);
              let binding_name = self.ensure_static_import_info(importee_idx, rec_id).to_string();
              self.exports.extend(decl.specifiers.iter().map(|specifier| {
                        self.snippet.object_property_kind_object_property(
                          &specifier.exported.name(),
                          match &specifier.local {
                            ast::ModuleExportName::IdentifierName(ident) => {
                              Expression::StaticMemberExpression(
                                self.snippet.builder.alloc_static_member_expression(
                                  SPAN,
                                  self.snippet.id_ref_expr(&binding_name, SPAN),
                                  self.snippet.builder.identifier_name(SPAN, ident.name.as_str()),
                                  false,
                                ),
                              )
                            }
                            ast::ModuleExportName::StringLiteral(str) => {
                              Expression::ComputedMemberExpression(
                                self.snippet.builder.alloc_computed_member_expression(
                                  SPAN,
                                  self.snippet.id_ref_expr(&binding_name, SPAN),
                                  self.snippet.builder.expression_string_literal(
                                    SPAN, str.value.as_str(), None
                                  ),
                                  false,
                                ),
                              )
                            }
                            ast::ModuleExportName::IdentifierReference(_) => {
                              unreachable!(
                                "ModuleExportName IdentifierReference is invalid in ExportNamedDeclaration with source"
                              )
                            }
                          },
                          matches!(specifier.exported, ast::ModuleExportName::StringLiteral(_))
                        )
                      }));
              if let Some(stmt) =
                self.create_load_exports_call_stmt(importee, &binding_name, decl.span)
              {
                program_body.push(stmt);
              }
            } else if let Some(decl) = &mut decl.declaration {
              match decl {
                ast::Declaration::VariableDeclaration(var_decl) => {
                  // export var foo = 1
                  // export var { foo, bar } = { foo: 1, bar: 2 }
                  self.exports.extend(var_decl.declarations.iter().flat_map(|decl| {
                    decl.id.get_binding_identifiers().into_iter().map(|ident| {
                      self.snippet.object_property_kind_object_property(
                        ident.name.as_str(),
                        self.snippet.id_ref_expr(ident.name.as_str(), SPAN),
                        false,
                      )
                    })
                  }));
                }
                ast::Declaration::FunctionDeclaration(fn_decl) => {
                  // export function foo() {}
                  let id = fn_decl.id.as_ref().unwrap().name.as_str();
                  self.exports.push(self.snippet.object_property_kind_object_property(
                    id,
                    self.snippet.id_ref_expr(id, SPAN),
                    false,
                  ));
                }
                ast::Declaration::ClassDeclaration(cls_decl) => {
                  // export class Foo {}
                  let id = cls_decl.id.as_ref().unwrap().name.as_str();
                  self.exports.push(self.snippet.object_property_kind_object_property(
                    id,
                    self.snippet.id_ref_expr(id, SPAN),
                    false,
                  ));
                }
                _ => unreachable!("doesn't support ts now"),
              }
              program_body.push(ast::Statement::from(decl.take_in(self.alloc)));
            } else {
              // export { foo, bar as bar2 }
              decl.specifiers.iter().for_each(|specifier| {
                if let Some(symbol_id) = scoping.get_root_binding(specifier.local.name().into()) {
                  self
                    .named_exports
                    .insert(specifier.exported.name(), NamedExport { local_binding: symbol_id });
                } else {
                  // TODO: export undefined variable
                }
              });
            }
          }
          ast::ModuleDeclaration::ExportDefaultDeclaration(decl) => match &mut decl.declaration {
            ast::ExportDefaultDeclarationKind::FunctionDeclaration(function) => {
              if let Some(id) = &function.id {
                self.exports.push(self.snippet.object_property_kind_object_property(
                  "default",
                  self.snippet.id_ref_expr(&id.name, SPAN),
                  false,
                ));
              } else {
                function.id = Some(self.snippet.id("__rolldown_default__", SPAN));
                self.exports.push(self.snippet.object_property_kind_object_property(
                  "default",
                  self.snippet.id_ref_expr("__rolldown_default__", SPAN),
                  false,
                ));
              }
              program_body.push(ast::Statement::FunctionDeclaration(ArenaBox::new_in(
                function.as_mut().take_in(self.alloc),
                self.alloc,
              )));
            }
            ast::ExportDefaultDeclarationKind::ClassDeclaration(class) => {
              if let Some(id) = &class.id {
                self.exports.push(self.snippet.object_property_kind_object_property(
                  "default",
                  self.snippet.id_ref_expr(&id.name, SPAN),
                  false,
                ));
              } else {
                class.id = Some(self.snippet.id("__rolldown_default__", SPAN));
                self.exports.push(self.snippet.object_property_kind_object_property(
                  "default",
                  self.snippet.id_ref_expr("__rolldown_default__", SPAN),
                  false,
                ));
              }
              program_body.push(ast::Statement::ClassDeclaration(ArenaBox::new_in(
                class.as_mut().take_in(self.alloc),
                self.alloc,
              )));
            }
            expr @ ast::match_expression!(ExportDefaultDeclarationKind) => {
              let expr = expr.to_expression_mut();
              // Transform `export default [expression]` => `var __rolldown_default__ = [expression]`
              program_body
                .push(self.snippet.var_decl_stmt("__rolldown_default__", expr.take_in(self.alloc)));
              self.exports.push(self.snippet.object_property_kind_object_property(
                "default",
                self.snippet.id_ref_expr("__rolldown_default__", SPAN),
                false,
              ));
            }
            unhandled_kind => {
              unreachable!("Unexpected export default declaration kind: {unhandled_kind:#?}");
            }
          },
          ast::ModuleDeclaration::ExportAllDeclaration(export_all_decl) => {
            let rec_id = self.module.imports[&export_all_decl.span];
            let rec = &self.module.import_records[rec_id];
            let Some(importee_idx) = rec.resolved_module else { return };
            let importee = &self.modules[importee_idx];
            self.dependencies.insert(importee_idx);
            let binding_name = self.ensure_static_import_info(importee_idx, rec_id).to_string();
            if let Some(stmt) =
              self.create_load_exports_call_stmt(importee, &binding_name, export_all_decl.span)
            {
              program_body.push(stmt);
            }
            if let Some(stmt) =
              self.create_re_export_call_stmt(importee, &binding_name, export_all_decl.span)
            {
              program_body.push(stmt);
            }
          }
          ast::ModuleDeclaration::TSExportAssignment(_)
          | ast::ModuleDeclaration::TSNamespaceExportDeclaration(_) => {
            // Typescript code should be pre-processed by rolldown. If it doesn't, it means there's error. Instead of panic, we'll just keep
            // the original code.
            program_body.push(node);
          }
        }
      }
      _ => {
        program_body.push(node);
      }
    }
  }

  pub fn ensure_static_import_info(
    &mut self,
    importee_idx: ModuleIdx,
    rec_id: ImportRecordIdx,
  ) -> &str {
    self.generated_static_import_infos.entry(importee_idx).or_insert_with(|| {
      let importee = &self.modules[importee_idx];

      format!("import_{}_{}{}", importee.repr_name(), self.unique_index, rec_id.raw())
    })
  }

  pub fn module_exports_name(&self) -> &'static str {
    if self.module.exports_kind.is_commonjs() {
      "module.exports"
    } else {
      MODULE_EXPORTS_NAME_FOR_ESM
    }
  }

  pub fn generate_runtime_module_register_for_hmr(
    &mut self,
    scoping: &Scoping,
  ) -> Vec<ast::Statement<'ast>> {
    let mut ret = vec![];
    if self.module.exports_kind == rolldown_common::ExportsKind::Esm {
      let binding_name_for_namespace_object_ref = self.module_exports_name();

      ret.extend(self.generate_declaration_of_module_namespace_object(
        binding_name_for_namespace_object_ref,
        scoping,
      ));
    }
    ret.push(self.create_register_module_stmt());

    // let module_exports =
    //   match self.module.exports_kind {
    //     rolldown_common::ExportsKind::Esm => {
    //       ret.extend(self.generate_declaration_of_module_namespace_object(
    //         &binding_name_for_namespace_object_ref,
    //       ));

    //       // { exports: namespace }
    //       ast::Argument::ObjectExpression(self.snippet.builder.alloc_object_expression(
    //         SPAN,
    //         self.snippet.builder.vec1(self.snippet.builder.object_property_kind_object_property(
    //           SPAN,
    //           PropertyKind::Init,
    //           self.snippet.builder.property_key_static_identifier(SPAN, "exports"),
    //           self.snippet.id_ref_expr(&binding_name_for_namespace_object_ref, SPAN),
    //           true,
    //           false,
    //           false,
    //         )),
    //       ))
    //     }
    //     rolldown_common::ExportsKind::CommonJs => {
    //       // `module`
    //       ast::Argument::Identifier(self.snippet.builder.alloc_identifier_reference(SPAN, "module"))
    //     }
    //     rolldown_common::ExportsKind::None => ast::Argument::ObjectExpression(
    //       // `{}`
    //       self.snippet.builder.alloc_object_expression(SPAN, self.snippet.builder.vec()),
    //     ),
    //   };

    // // __rolldown_runtime__.registerModule(moduleId, module)
    // let arguments = self.snippet.builder.vec_from_array([
    //   ast::Argument::StringLiteral(self.snippet.builder.alloc_string_literal(
    //     SPAN,
    //     self.snippet.builder.str(&self.module.stable_id),
    //     None,
    //   )),
    //   module_exports,
    // ]);

    // let register_call = self.snippet.builder.alloc_call_expression(
    //   SPAN,
    //   self.snippet.id_ref_expr("__rolldown_runtime__.registerModule", SPAN),
    //   NONE,
    //   arguments,
    //   false,
    // );

    // ret.push(ast::Statement::ExpressionStatement(
    //   self
    //     .snippet
    //     .builder
    //     .alloc_expression_statement(SPAN, ast::Expression::CallExpression(register_call)),
    // ));

    ret
  }

  pub fn rewrite_hot_accept_call_deps(&self, call_expr: &mut ast::CallExpression<'ast>) {
    // Check whether the callee is `import.meta.hot.accept`.
    if !call_expr.callee.is_import_meta_hot_accept() {
      return;
    }

    if call_expr.arguments.is_empty() {
      // `import.meta.hot.accept()`
      return;
    }

    match &mut call_expr.arguments[0] {
      ast::Argument::StringLiteral(string_literal) => {
        // `import.meta.hot.accept('./dep.js', ...)`
        let import_record = &self.module.import_records
          [self.module.hmr_info.module_request_to_import_record_idx[string_literal.value.as_str()]];
        let Some(module_idx) = import_record.resolved_module else { return };
        // Use stable module ID for consistent runtime lookup
        string_literal.value = self.snippet.builder.str(self.modules[module_idx].stable_id());
      }
      ast::Argument::ArrayExpression(array_expression) => {
        // `import.meta.hot.accept(['./dep1.js', './dep2.js'], ...)`
        array_expression.elements.iter_mut().for_each(|element| {
          if let ast::ArrayExpressionElement::StringLiteral(string_literal) = element {
            let import_record =
              &self.module.import_records[self.module.hmr_info.module_request_to_import_record_idx
                [string_literal.value.as_str()]];
            let Some(module_idx) = import_record.resolved_module else { return };
            // Use stable module ID for consistent runtime lookup
            string_literal.value = self.snippet.builder.str(self.modules[module_idx].stable_id());
          }
        });
      }
      _ => {}
    }
  }

  pub fn rewrite_import_meta_hot(&self, expr: &mut ast::Expression<'ast>) {
    if expr.is_import_meta_hot() {
      let hot_name = format!("hot_{}", self.module.repr_name);
      *expr = self.snippet.id_ref_expr(&hot_name, SPAN);
    }
  }

  fn create_load_exports_call_stmt(
    &mut self,
    importee: &Module,
    binding_name: &str,
    span: Span,
  ) -> Option<Statement<'ast>> {
    if self.imports.contains(&importee.idx()) {
      return None;
    }
    self.imports.insert(importee.idx());

    // Use stable module ID for consistent runtime lookup
    let id = importee.stable_id();
    let interop = match importee {
      Module::Normal(importee) => self.module.interop(importee),
      Module::External(_) => None,
    };
    let call_expr = self.snippet.call_expr_with_arg_expr(
      self.snippet.literal_prop_access_member_expr_expr("__rolldown_runtime__", "loadExports"),
      self.snippet.string_literal_expr(id, SPAN),
      false,
    );

    let stmt = self.snippet.variable_declarator_require_call_stmt(
      binding_name,
      self.snippet.to_esm_call_with_interop("__rolldown_runtime__.__toESM", call_expr, interop),
      span,
    );
    Some(stmt)
  }

  fn create_static_import_stmt_from_external_module(
    &mut self,
    importee: &ExternalModule,
    binding_name: &str,
    _span: Span,
  ) {
    if self.generated_static_import_stmts_from_external.contains_key(&importee.idx) {
      return;
    }

    let module_request = &importee.id;

    // import * as [binding_name] from 'external';
    let stmt = self.snippet.import_star_stmt(module_request, binding_name);

    self.generated_static_import_stmts_from_external.insert(importee.idx, stmt);
  }

  fn create_re_export_call_stmt(
    &mut self,
    importee: &Module,
    binding_name: &str,
    span: Span,
  ) -> Option<Statement<'ast>> {
    if self.re_export_all_dependencies.contains(&importee.idx()) {
      return None;
    }
    self.re_export_all_dependencies.insert(importee.idx());

    let self_exports = self.module_exports_name();

    let call_expr = self.snippet.call_expr_with_2arg_expr(
      self.snippet.literal_prop_access_member_expr_expr("__rolldown_runtime__", "__reExport"),
      self.snippet.id_ref_expr(self_exports, SPAN),
      self.snippet.id_ref_expr(binding_name, SPAN),
    );

    Some(ast::Statement::ExpressionStatement(
      self.snippet.builder.alloc_expression_statement(span, call_expr),
    ))
  }

  fn generate_declaration_of_module_namespace_object(
    &mut self,
    binding_name_for_namespace_object_ref: &str,
    scoping: &Scoping,
  ) -> Vec<ast::Statement<'ast>> {
    // TODO reexport external module

    // construct `{ prop_name: () => returned, ... }`
    let mut arg_obj_expr = self
      .snippet
      .builder
      .alloc_object_expression(SPAN, self.snippet.builder.vec_with_capacity(self.exports.len()));
    arg_obj_expr.properties.extend(self.exports.drain(..));
    arg_obj_expr.properties.extend(self.named_exports.iter().map(|(exported, named_export)| {
      let expr = if let Some(local_binding) = self.import_bindings.get(&named_export.local_binding)
      {
        self.snippet.id_ref_expr(local_binding, SPAN)
      } else {
        let name = scoping.symbol_name(named_export.local_binding);
        self.snippet.id_ref_expr(name, SPAN)
      };
      // Use computed property syntax for non-identifier export names (e.g., 'rolldown:exports')
      let computed = !is_validate_identifier_name(exported.as_str());
      self.snippet.object_property_kind_object_property(exported, expr, computed)
    }));

    // construct `__export(ns_name, { prop_name: () => returned, ... })`
    let export_call_expr = self.snippet.builder.expression_call(
      SPAN,
      self.snippet.id_ref_expr("__rolldown_runtime__.__exportAll", SPAN),
      NONE,
      self
        .snippet
        .builder
        .vec_from_array([ast::Argument::ObjectExpression(arg_obj_expr.into_in(self.alloc))]),
      false,
    );

    // construct `var [binding_name_for_namespace_object_ref] = __exportAll({ prop_name: () => returned, ... })`
    let decl_stmt =
      self.snippet.var_decl_stmt(binding_name_for_namespace_object_ref, export_call_expr);
    vec![decl_stmt]
  }

  // Rewrite `import(...)` to sensible form.
  pub fn try_rewrite_dynamic_import(&self, it: &mut ast::Expression<'ast>) {
    let ast::Expression::ImportExpression(import_expr) = it else {
      return;
    };

    let Some(rec_idx) = self.module.imports.get(&import_expr.span) else {
      return;
    };

    let Some(importee_idx) = self.module.import_records[*rec_idx].resolved_module else {
      return;
    };

    let Module::Normal(importee) = &self.modules[importee_idx] else {
      // Not a normal module, skip
      return;
    };

    // Handle lazy proxy modules - rewrite to mirror the proxy module's runtime contract.
    //
    // In a regular full build, scope finalizer rewrites `import('./foo')` to point at the
    // proxy module's chunk URL. That chunk's content is `proxy-module-template.js`, which
    // exposes `'rolldown:exports'` at the top level so consumers can do
    // `.then(__unwrap_lazy_compilation_entry).then(m => m.X)`.
    //
    // In HMR partial bundles there's no separately bundled proxy chunk - the proxy module's
    // body gets wrapped inside a `createEsmInitializer` and its top-level `export` is lost.
    // To keep the same surface as the full build, we rewrite the dynamic import to:
    //
    //   import(`/@vite/lazy?id=...&clientId=...`)
    //     .then(() => __rolldown_runtime__.loadExports("<stable_proxy_id>"))
    //
    // After the partial bundle evaluates, the proxy module is registered under
    // `<stable_proxy_id>` with a `'rolldown:exports'` getter (set up by `__exportAll` inside
    // the init wrapper). Reading it back via `loadExports` yields the namespace object that
    // the existing `__unwrap_lazy_compilation_entry` chain expects.
    //
    // TODO: hyf0 should switch to a more robust way to identify lazy proxy modules
    if importee.id.contains("?rolldown-lazy=1") {
      // Build: encodeURIComponent(importee.id)
      let encode_call = ast::Expression::CallExpression(self.builder.alloc_call_expression(
        SPAN,
        self.snippet.id_ref_expr("encodeURIComponent", SPAN),
        NONE,
        self.builder.vec1(ast::Argument::StringLiteral(self.builder.alloc_string_literal(
          SPAN,
          self.builder.str(&importee.id),
          None,
        ))),
        false,
      ));

      // Build template literal: `/@vite/lazy?id=${encodeURIComponent(importee.id)}&clientId=${__rolldown_runtime__.clientId}`
      let url_expr = {
        let quasis = self.builder.vec_from_iter([
          self.builder.template_element(
            SPAN,
            ast::TemplateElementValue { raw: self.builder.str("/@vite/lazy?id="), cooked: None },
            false,
            false,
          ),
          self.builder.template_element(
            SPAN,
            ast::TemplateElementValue { raw: self.builder.str("&clientId="), cooked: None },
            false,
            false,
          ),
          self.builder.template_element(
            SPAN,
            ast::TemplateElementValue { raw: self.builder.str(""), cooked: None },
            true,
            false,
          ),
        ]);
        let expressions = self.builder.vec_from_iter([
          encode_call,
          self.snippet.literal_prop_access_member_expr_expr("__rolldown_runtime__", "clientId"),
        ]);
        self.builder.expression_template_literal(SPAN, quasis, expressions)
      };

      // Build: import(`/@vite/lazy?id=...&clientId=...`)
      let import_expr = self.builder.expression_import(SPAN, url_expr, None, None);

      // Build: __rolldown_runtime__.loadExports("<stable_proxy_id>")
      let load_exports_call = ast::Expression::CallExpression(self.builder.alloc_call_expression(
        SPAN,
        self.snippet.id_ref_expr("__rolldown_runtime__.loadExports", SPAN),
        NONE,
        self.builder.vec1(ast::Argument::StringLiteral(self.builder.alloc_string_literal(
          SPAN,
          self.builder.str(&importee.stable_id),
          None,
        ))),
        false,
      ));

      // Build: () => __rolldown_runtime__.loadExports("<stable_proxy_id>")
      let arrow_fn = self.builder.expression_arrow_function(
        SPAN,
        /* expression */ true,
        /* async */ false,
        NONE,
        self.builder.formal_parameters(
          SPAN,
          ast::FormalParameterKind::ArrowFormalParameters,
          self.builder.vec(),
          NONE,
        ),
        NONE,
        self.builder.function_body(
          SPAN,
          self.builder.vec(),
          self.builder.vec1(ast::Statement::ExpressionStatement(
            self.builder.alloc_expression_statement(SPAN, load_exports_call),
          )),
        ),
      );

      // Build: import(...).then(() => __rolldown_runtime__.loadExports("..."))
      let then_callee =
        Expression::StaticMemberExpression(self.builder.alloc_static_member_expression(
          SPAN,
          import_expr,
          self.builder.identifier_name(SPAN, "then"),
          false,
        ));

      *it = self.builder.expression_call(
        SPAN,
        then_callee,
        NONE,
        self.builder.vec1(ast::Argument::from(arrow_fn)),
        false,
      );
      return;
    }

    // FIXME: consider about CommonJS interop
    let is_importee_cjs = importee.exports_kind == rolldown_common::ExportsKind::CommonJs;

    // __rolldown_runtime__.loadExports('./foo.js')
    // Use stable module ID for consistent runtime lookup
    let mut load_exports_call_expr =
      ast::Expression::CallExpression(self.snippet.builder.alloc_call_expression(
        SPAN,
        self.snippet.id_ref_expr("__rolldown_runtime__.loadExports", SPAN),
        NONE,
        self.snippet.builder.vec1(ast::Argument::StringLiteral(
          self.snippet.builder.alloc_string_literal(
            SPAN,
            self.snippet.builder.str(&importee.stable_id),
            None,
          ),
        )),
        false,
      ));

    if is_importee_cjs {
      let is_node_cjs = importee.def_format.is_commonjs();

      let mut args = self.snippet.builder.vec1(ast::Argument::from(load_exports_call_expr));
      if is_node_cjs {
        args.push(ast::Argument::from(self.snippet.builder.expression_numeric_literal(
          SPAN,
          1.0,
          None,
          ast::NumberBase::Decimal,
        )));
      }

      // __rolldown_runtime__.__toDynamicImportESM(__rolldown_runtime__.loadExports('./foo.js'), node_mode)
      load_exports_call_expr = self.snippet.builder.expression_call(
        SPAN,
        self.snippet.id_ref_expr("__rolldown_runtime__.__toDynamicImportESM", SPAN),
        NONE,
        args,
        false,
      );
    }

    if let Some(init_fn_name) = self.affected_module_idx_to_init_fn_name.get(&importee_idx) {
      // If the importee is in the propagation chain, we need to call the init function to re-execute the module.
      // Turn `import('./foo.js')` into `(init_foo(), Promise.resolve().then(() => __rolldown_runtime__.loadExports('./foo.js')))`

      // init_foo()
      let init_fn_call = self.snippet.builder.alloc_call_expression(
        SPAN,
        self.snippet.id_ref_expr(init_fn_name, SPAN),
        NONE,
        self.snippet.builder.vec(),
        false,
      );

      // Promise.resolve().then(() => __rolldown_runtime__.loadExports('./foo.js'))
      let promise_resolve_then_load_exports =
        self.snippet.promise_resolve_then_call_expr(load_exports_call_expr);

      // (init_foo(), Promise.resolve().then(() => __rolldown_runtime__.loadExports('./foo.js')))
      let ret_expr =
        ast::Expression::SequenceExpression(self.snippet.builder.alloc_sequence_expression(
          SPAN,
          self.snippet.builder.vec_from_array([
            ast::Expression::CallExpression(init_fn_call),
            promise_resolve_then_load_exports,
          ]),
        ));
      *it = ret_expr;
    } else {
      // Turn `import('./foo.js')` into `Promise.resolve().then(() => __rolldown_runtime__.loadExports('./foo.js'))`

      // `Promise.resolve().then(() => __rolldown_runtime__.loadExports('./foo.js'))`
      *it = self.snippet.promise_resolve_then_call_expr(load_exports_call_expr);
    }
  }

  pub fn try_rewrite_require(
    &self,
    it: &mut ast::Expression<'ast>,
    ctx: &oxc_traverse::TraverseCtx<'ast, ()>,
  ) {
    let scoping = ctx.scoping();

    // Rewrite standalone `require` to `__rolldown_runtime__.loadExports`
    if let Some(id_ref) = it.as_identifier()
      && id_ref.name == CJS_REQUIRE_REF_STR
      && id_ref.is_global_reference(scoping)
      && !ctx.parent().is_call_expression()
    {
      *it =
        self.snippet.literal_prop_access_member_expr_expr("__rolldown_runtime__", "loadExports");
    }

    // Rewrite `require(...)` to `(require_xxx(), __rolldown_runtime__.loadExports())` or keep it as is for external module importee.
    let ast::Expression::CallExpression(call_expr) = it else {
      return;
    };

    if !call_expr
      .callee
      .as_identifier()
      .is_some_and(|id| id.name == CJS_REQUIRE_REF_STR && id.is_global_reference(scoping))
    {
      return;
    }

    let Some(rec_idx) = self.module.imports.get(&call_expr.span) else {
      return;
    };

    let rec = &self.module.import_records[*rec_idx];
    let Some(importee_idx) = rec.resolved_module else {
      return;
    };

    let Module::Normal(importee) = &self.modules[importee_idx] else {
      // Not a normal module, skip
      return;
    };

    let is_importee_cjs = importee.exports_kind == rolldown_common::ExportsKind::CommonJs;

    // Use stable module ID for consistent runtime lookup
    let load_exports_call = self.snippet.call_expr_with_arg_expr(
      self.snippet.literal_prop_access_member_expr_expr("__rolldown_runtime__", "loadExports"),
      self.snippet.string_literal_expr(&importee.stable_id, SPAN),
      false,
    );

    let load_exports_expr = if importee.meta.has_lazy_export() || is_importee_cjs {
      // Note that HMR finalizer is only able to see scanner-level exports_kind, this means that the result
      // from `determine_module_exports_kind` is not available here. So we have to use some heuristics to determine
      // whether the importee is CommonJS or has lazy export, and handle them in a special way.
      //
      // 1. For the case of `is_importee_cjs`,
      // the runtime will always have `module.exports`. This is determined in `determine_module_exports_kind`.
      //
      // 2. For the case of `has_lazy_export`,
      // here we're inside `try_rewrite_require`, which means the original code is `require(...)`.
      //
      // Modules that have lazy export is of these `ModuleType`: `Json`, `Text`, `Base64`, `Dataurl`.
      // These data type does not have `export`, `module.exports` or any export keyword at runtime,
      // so they're `ExportsKind::None` by default.
      //
      // For those lazy export modules, if `ImportKind` is `Require`, which is the case here,
      // and the importee has `ExportsKind::None`, then the importee's `WrapKind` is set to `WrapKind::Cjs`.
      // So here we know for sure that the importee is using `module.exports` at runtime.
      // So `loadExports(id)` returns the value directly.
      //
      // This is a way to mimic the same mechanism of `determine_module_exports_kind`.
      //
      // TODO(hana): we should think about a more robust way to track the consolidated export type of a module in the future.
      // Listing all the special cases like this is error-prone.
      load_exports_call
    } else if rec.meta.contains(ImportRecordMeta::JsonModule) {
      // Vite-mode JSON: ESM-wrapped at runtime, unwrap to the JSON value.
      let to_commonjs_call = self.snippet.call_expr_with_arg_expr(
        self.snippet.literal_prop_access_member_expr_expr("__rolldown_runtime__", "__toCommonJS"),
        load_exports_call,
        false,
      );
      Expression::from(self.snippet.builder.member_expression_static(
        SPAN,
        to_commonjs_call,
        self.snippet.id_name("default", SPAN),
        false,
      ))
    } else {
      self.snippet.call_expr_with_arg_expr(
        self.snippet.literal_prop_access_member_expr_expr("__rolldown_runtime__", "__toCommonJS"),
        load_exports_call,
        false,
      )
    };

    if let Some(init_fn_name) = self.affected_module_idx_to_init_fn_name.get(&importee_idx) {
      // If the importee is in the current patch, call init before loading exports
      // Turn `require('./foo.js')` into `(init_foo(), __rolldown_runtime__.loadExports('./foo.js'))`
      *it = self
        .snippet
        .seq2_in_paren_expr(self.snippet.call_expr_expr(init_fn_name), load_exports_expr);
    } else {
      // Importee is not in current patch (already executed by client), just load its exports
      // Turn `require('./foo.js')` into `__rolldown_runtime__.loadExports('./foo.js')`
      *it = load_exports_expr;
    }
  }
}

pub struct NamedExport {
  pub local_binding: SymbolId,
}