From bf3c9b65a8fe8e17338c3d21d695909d9eeb175e Mon Sep 17 00:00:00 2001
From: CPunisher <1343316114@qq.com>
Date: Sat, 23 Nov 2024 13:51:28 +0800
Subject: [PATCH] remove usage analysis for script

---
 crates/swc_typescript/src/fast_dts/mod.rs     | 24 ++++++++++---------
 .../src/fast_dts/visitors/type_usage.rs       | 22 +++--------------
 2 files changed, 16 insertions(+), 30 deletions(-)

diff --git a/crates/swc_typescript/src/fast_dts/mod.rs b/crates/swc_typescript/src/fast_dts/mod.rs
index 984fe2040b3e..c2049ade8aab 100644
--- a/crates/swc_typescript/src/fast_dts/mod.rs
+++ b/crates/swc_typescript/src/fast_dts/mod.rs
@@ -78,10 +78,6 @@ impl FastDts {
 
 impl FastDts {
     pub fn transform(&mut self, program: &mut Program) -> Vec<DtsIssue> {
-        self.used_ids.extend(TypeUsageAnalyzer::analyze(
-            program,
-            self.internal_annotations.as_ref(),
-        ));
         match program {
             Program::Module(module) => self.transform_module_body(&mut module.body, false),
             Program::Script(script) => self.transform_script(script),
@@ -94,11 +90,17 @@ impl FastDts {
         items: &mut Vec<ModuleItem>,
         in_global_or_lit_module: bool,
     ) {
-        // 1. Transform.
+        // 1. Analyze usage
+        self.used_ids.extend(TypeUsageAnalyzer::analyze(
+            items,
+            self.internal_annotations.as_ref(),
+        ));
+
+        // 2. Transform.
         Self::remove_function_overloads_in_module(items);
         self.transform_module_items(items);
 
-        // 2. Strip export keywords in ts module blocks
+        // 3. Strip export keywords in ts module blocks
         for item in items.iter_mut() {
             if let Some(Stmt::Decl(Decl::TsModule(ts_module))) = item.as_mut_stmt() {
                 if ts_module.global || !ts_module.id.is_str() {
@@ -115,7 +117,7 @@ impl FastDts {
             }
         }
 
-        // 3. Report error for expando function and remove statements.
+        // 4. Report error for expando function and remove statements.
         self.report_error_for_expando_function_in_module(items);
         items.retain(|item| {
             item.as_stmt()
@@ -123,10 +125,10 @@ impl FastDts {
                 .unwrap_or(true)
         });
 
-        // 4. Remove unused imports and decls
+        // 5. Remove unused imports and decls
         self.remove_ununsed(items, in_global_or_lit_module);
 
-        // 5. Add empty export mark if there's any declaration that is used but not
+        // 6. Add empty export mark if there's any declaration that is used but not
         // exported to keep its privacy.
         let mut has_non_exported_stmt = false;
         let mut has_export = false;
@@ -416,8 +418,8 @@ impl FastDts {
         for stmt in stmts {
             match stmt {
                 Stmt::Decl(decl) => match decl {
-                    Decl::Fn(fn_decl) => collector.add_fn_decl(fn_decl, true),
-                    Decl::Var(var_decl) => collector.add_var_decl(var_decl, true),
+                    Decl::Fn(fn_decl) => collector.add_fn_decl(fn_decl, false),
+                    Decl::Var(var_decl) => collector.add_var_decl(var_decl, false),
                     _ => (),
                 },
                 Stmt::Expr(expr_stmt) => {
diff --git a/crates/swc_typescript/src/fast_dts/visitors/type_usage.rs b/crates/swc_typescript/src/fast_dts/visitors/type_usage.rs
index 6bc4a30f012c..96b562bf8639 100644
--- a/crates/swc_typescript/src/fast_dts/visitors/type_usage.rs
+++ b/crates/swc_typescript/src/fast_dts/visitors/type_usage.rs
@@ -7,7 +7,7 @@ use rustc_hash::{FxHashMap, FxHashSet};
 use swc_common::{BytePos, Spanned, SyntaxContext};
 use swc_ecma_ast::{
     Class, Decl, ExportDecl, ExportDefaultDecl, ExportDefaultExpr, Function, Id, Ident,
-    ModuleExportName, ModuleItem, NamedExport, Program, Script, TsEntityName, TsExportAssignment,
+    ModuleExportName, ModuleItem, NamedExport, TsEntityName, TsExportAssignment,
     TsExprWithTypeArgs,
 };
 use swc_ecma_visit::{Visit, VisitWith};
@@ -23,7 +23,7 @@ pub struct TypeUsageAnalyzer<'a> {
 
 impl TypeUsageAnalyzer<'_> {
     pub fn analyze(
-        program: &Program,
+        module_items: &Vec<ModuleItem>,
         internal_annotations: Option<&FxHashSet<BytePos>>,
     ) -> FxHashSet<Id> {
         // Create a fake entry
@@ -37,7 +37,7 @@ impl TypeUsageAnalyzer<'_> {
             source: None,
             internal_annotations,
         };
-        program.visit_with(&mut analyzer);
+        module_items.visit_with(&mut analyzer);
 
         // Reachability
         let mut used_ids = FxHashSet::default();
@@ -238,20 +238,4 @@ impl Visit for TypeUsageAnalyzer<'_> {
             item.visit_children_with(self);
         }
     }
-
-    fn visit_script(&mut self, node: &Script) {
-        for stmt in &node.body {
-            // Skip statements
-            if !stmt.is_decl()
-                || self
-                    .internal_annotations
-                    .map_or(false, |internal_annotations| {
-                        internal_annotations.contains(&stmt.span_lo())
-                    })
-            {
-                continue;
-            }
-            stmt.visit_children_with(self);
-        }
-    }
 }