fix(es/typescrupt): Fix ASI issue in fast ts strip (#9332)

**Related issue:**

- Closes #9331

.changeset/long-bears-joke.md

@@ -0,0 +1,5 @@
+---
+swc_fast_ts_strip: patch
+---
+
+fix(es/typescrupt): Fix ASI issue in fast ts strip

crates/swc_fast_ts_strip/src/lib.rs

@@ -20,7 +20,7 @@ use swc_ecma_ast::{
 };
 use swc_ecma_parser::{
     lexer::Lexer,
-    token::{IdentLike, KnownIdent, Token, TokenAndSpan, Word},
+    token::{BinOpToken, IdentLike, KnownIdent, Token, TokenAndSpan, Word},
     Capturing, Parser, StringInput, Syntax, TsSyntax,
 };
 use swc_ecma_transforms_base::{
@@ -375,6 +375,44 @@ impl TsStrip {
     fn get_prev_token(&self, pos: BytePos) -> &TokenAndSpan {
         &self.tokens[self.get_prev_token_index(pos)]
     }
+
+    fn fix_asi(&mut self, span: Span) {
+        let index = self.get_prev_token_index(span.lo);
+        if index == 0 {
+            // Skip if the token is the first token.
+            return;
+        }
+
+        let TokenAndSpan {
+            token: prev_token,
+            span: prev_span,
+            ..
+        } = &self.tokens[index - 1];
+
+        let index = self.get_prev_token_index(span.hi);
+        if index == self.tokens.len() - 1 {
+            // Skip if the token is the last token.
+            return;
+        }
+
+        let TokenAndSpan { token, .. } = &self.tokens[index + 1];
+
+        // Add a semicolon if the next token is `[`, `(`, `/`, `+`, or `-`
+        match token {
+            Token::LParen
+            | Token::LBracket
+            | Token::BinOp(BinOpToken::Add | BinOpToken::Sub | BinOpToken::Div) => {
+                if prev_token == &Token::Semi {
+                    self.add_overwrite(prev_span.lo, b';');
+                    return;
+                }
+
+                self.add_overwrite(span.lo, b';');
+            }
+
+            _ => {}
+        }
+    }
 }
 
 impl Visit for TsStrip {
@@ -469,6 +507,7 @@ impl Visit for TsStrip {
     fn visit_class_decl(&mut self, n: &ClassDecl) {
         if n.declare {
             self.add_replacement(n.span());
+            self.fix_asi(n.span());
             return;
         }
 
@@ -549,12 +588,19 @@ impl Visit for TsStrip {
             self.add_replacement(definite_mark.span);
         }
 
+        if n.value.is_none() && n.key.as_ident().filter(|k| k.sym == "static").is_some() {
+            if let Some(type_ann) = &n.type_ann {
+                self.add_overwrite(type_ann.span.lo, b';');
+            }
+        }
+
         n.visit_children_with(self);
     }
 
     fn visit_export_all(&mut self, n: &ExportAll) {
         if n.type_only {
             self.add_replacement(n.span);
+            self.fix_asi(n.span);
             return;
         }
 
@@ -568,6 +614,7 @@ impl Visit for TsStrip {
             | swc_ecma_ast::Decl::TsEnum(_)
             | swc_ecma_ast::Decl::TsModule(_) => {
                 self.add_replacement(n.span);
+                self.fix_asi(n.span);
             }
 
             _ => {
@@ -587,6 +634,7 @@ impl Visit for TsStrip {
     fn visit_import_decl(&mut self, n: &ImportDecl) {
         if n.type_only {
             self.add_replacement(n.span);
+            self.fix_asi(n.span);
             return;
         }
 
@@ -613,6 +661,7 @@ impl Visit for TsStrip {
     fn visit_named_export(&mut self, n: &NamedExport) {
         if n.type_only {
             self.add_replacement(n.span);
+            self.fix_asi(n.span);
             return;
         }
 
@@ -672,6 +721,7 @@ impl Visit for TsStrip {
     fn visit_ts_enum_decl(&mut self, e: &TsEnumDecl) {
         if e.declare {
             self.add_replacement(e.span);
+            self.fix_asi(e.span);
             return;
         }
 
@@ -695,6 +745,7 @@ impl Visit for TsStrip {
     fn visit_ts_import_equals_decl(&mut self, n: &TsImportEqualsDecl) {
         if n.is_type_only {
             self.add_replacement(n.span);
+            self.fix_asi(n.span);
             return;
         }
 
@@ -718,11 +769,13 @@ impl Visit for TsStrip {
 
     fn visit_ts_interface_decl(&mut self, n: &TsInterfaceDecl) {
         self.add_replacement(n.span);
+        self.fix_asi(n.span);
     }
 
     fn visit_ts_module_decl(&mut self, n: &TsModuleDecl) {
         if n.declare || matches!(n.id, TsModuleName::Str(..)) {
             self.add_replacement(n.span);
+            self.fix_asi(n.span);
             return;
         }
 
@@ -737,6 +790,7 @@ impl Visit for TsStrip {
     fn visit_ts_namespace_decl(&mut self, n: &TsNamespaceDecl) {
         if n.declare {
             self.add_replacement(n.span);
+            self.fix_asi(n.span);
             return;
         }
 
@@ -771,6 +825,7 @@ impl Visit for TsStrip {
 
     fn visit_ts_type_alias_decl(&mut self, n: &TsTypeAliasDecl) {
         self.add_replacement(n.span);
+        self.fix_asi(n.span);
     }
 
     fn visit_ts_type_ann(&mut self, n: &TsTypeAnn) {
@@ -803,6 +858,7 @@ impl Visit for TsStrip {
     fn visit_var_decl(&mut self, n: &VarDecl) {
         if n.declare {
             self.add_replacement(n.span);
+            self.fix_asi(n.span);
             return;
         }
 

crates/swc_fast_ts_strip/tests/fixture/issue-9331.js

@@ -0,0 +1,45 @@
+f
+;              
+(1)
+
+function f() { }
+
+
+f
+;            
+(1)
+
+f
+;                            
+(1)
+
+5
+;              
+-1
+
+
+f
+;                   
+
+
+[1].map(() => 1)
+
+f
+;                     
+/1/
+
+f
+                     ;
+
+/1/
+
+
+class foo {
+    static;    
+
+    foo() { }
+}
+
+2
+;              
++ 3

crates/swc_fast_ts_strip/tests/fixture/issue-9331.transform.js

@@ -0,0 +1,24 @@
+f;
+1;
+function f() {}
+f;
+1;
+f;
+1;
+5;
+-1;
+f;
+[
+    1
+].map(()=>1);
+f;
+/1/;
+f;
+/1/;
+class foo {
+    static;
+    foo() {}
+}
+2;
++3;
+export { };

crates/swc_fast_ts_strip/tests/fixture/issue-9331.ts

@@ -0,0 +1,45 @@
+f
+interface I { }
+(1)
+
+function f() { }
+
+
+f
+type x = any;
+(1)
+
+f
+import type { x } from 'foo';
+(1)
+
+5
+interface I { }
+-1
+
+
+f
+declare class name {
+    constructor();
+}
+[1].map(() => 1)
+
+f
+declare var x: string;
+/1/
+
+f
+declare var y: string;
+declare var z: string;
+/1/
+
+
+class foo {
+    static: any
+    declare x: any
+    foo() { }
+}
+
+2
+export type { }
++ 3