fix(codegen): correct CRLF handling in comment processing

crates/oxc_codegen/src/comment.rs

@@ -9,6 +9,58 @@ use crate::{Codegen, LegalComment, options::CommentOptions};
 
 pub type CommentsMap = FxHashMap</* attached_to */ u32, Vec<Comment>>;
 
+/// Custom iterator that splits text on line terminators while handling CRLF as a single unit.
+/// This avoids creating empty strings between CR and LF characters.
+///
+/// # Example
+/// Standard split would turn `"line1\r\nline2"` into `["line1", "", "line2"]` because
+/// it treats \r and \n as separate terminators. This iterator correctly produces
+/// `["line1", "line2"]` by treating \r\n as a single terminator.
+struct LineTerminatorSplitter<'a> {
+    text: &'a str,
+    position: usize,
+}
+
+impl<'a> LineTerminatorSplitter<'a> {
+    fn new(text: &'a str) -> Self {
+        Self { text, position: 0 }
+    }
+}
+
+impl<'a> Iterator for LineTerminatorSplitter<'a> {
+    type Item = &'a str;
+
+    fn next(&mut self) -> Option<Self::Item> {
+        if self.position >= self.text.len() {
+            return None;
+        }
+
+        let start = self.position;
+        let chars = self.text[self.position..].char_indices();
+
+        for (i, c) in chars {
+            if is_line_terminator(c) {
+                let line = &self.text[start..start + i];
+                self.position = start + i + c.len_utf8();
+
+                // If this is CR followed by LF, skip the LF to treat CRLF as a single terminator
+                if c == '\r'
+                    && self.text.as_bytes().get(self.position).is_some_and(|&next| next == b'\n')
+                {
+                    self.position += 1;
+                }
+
+                return Some(line);
+            }
+        }
+
+        // Return the remaining text
+        let line = &self.text[start..];
+        self.position = self.text.len();
+        Some(line)
+    }
+}
+
 impl Codegen<'_> {
     pub(crate) fn build_comments(&mut self, comments: &[Comment]) {
         if self.options.comments == CommentOptions::disabled() {
@@ -132,8 +184,7 @@ impl Codegen<'_> {
                 self.print_str_escaping_script_close_tag(comment_source);
             }
             CommentKind::Block => {
-                // Print block comments with our own indentation.
-                for line in comment_source.split(is_line_terminator) {
+                for line in LineTerminatorSplitter::new(comment_source) {
                     if !line.starts_with("/*") {
                         self.print_indent();
                     }
@@ -167,7 +218,7 @@ impl Codegen<'_> {
             if comment.is_block() && text.contains(is_line_terminator) {
                 let mut buffer = String::with_capacity(text.len());
                 // Print block comments with our own indentation.
-                for line in text.split(is_line_terminator) {
+                for line in LineTerminatorSplitter::new(&text) {
                     if !line.starts_with("/*") {
                         buffer.push('\t');
                     }

crates/oxc_isolated_declarations/tests/fixtures/class-decorator.ts

@@ -1,13 +1,17 @@
 declare const decorator: any;
 
 export class Test1 {
-  /** This method will trigger the feature highlight dialog load/show based on dialogId and analyticsId */
+  /**
+   * This method will trigger the feature highlight dialog load/show based on dialogId and analyticsId
+   */
   @decorator
   property: (() => any) | undefined;
 }
 
 export class Test2 {
-  /** This method will trigger the feature highlight dialog load/show based on dialogId and analyticsI */
+  /**
+   * This method will trigger the feature highlight dialog load/show based on dialogId and analyticsI
+   */
   @decorator
   property: ((arg: any) => any) | undefined;
 }

crates/oxc_isolated_declarations/tests/fixtures/class.ts

@@ -20,17 +20,29 @@ export abstract class Qux {
 }
 
 export class Baz {
-  /** Just a comment */
+  /**
+   * Just a comment
+   */
   readonly prop1 = "some string";
-  /** Just a comment */
+  /**
+   * Just a comment
+   */
   prop2 = "another string";
-  /** Just a comment */
+  /**
+   * Just a comment
+   */
   private prop3 = "yet another string";
-  /** Just a comment */
+  /**
+   * Just a comment
+   */
   private prop4(): void {}
-  /** Just a comment */
+  /**
+   * Just a comment
+   */
   private static prop5 = "yet another string";
-  /** Just a comment */
+  /**
+   * Just a comment
+   */
   private static prop6(): void {}
 }
 
@@ -142,4 +154,4 @@ export class PrivateConstructorWithDefaultParameters {
 		readonly prop3: boolean = true,
 		normalParam: string = "normal",
 	) {}
-}
+}

crates/oxc_isolated_declarations/tests/fixtures/export-default.ts

@@ -1,6 +1,8 @@
 const defaultDelimitersClose = new Uint8Array([125, 125]);
 
-/** comment should be a leading comment of the class */
+/**
+ * comment should be a leading comment of the class
+ */
 export default class Tokenizer {
 	public delimiterClose: Uint8Array = defaultDelimitersClose;
 }

crates/oxc_isolated_declarations/tests/fixtures/export-default2.ts

@@ -1,4 +1,6 @@
-/** comment should be a leading comment of the arrow function */
+/**
+ * comment should be a leading comment of the arrow function
+ */
 export default () => {
   return 0;
 };

crates/oxc_isolated_declarations/tests/fixtures/strip-internal.ts

@@ -50,7 +50,9 @@ export interface StripInternalInterfaceSignatures {
    * @internal
    */
   internalProperty: number;
-  /**@internal */
+  /**
+   * @internal
+   */
   new (): any;
 }
 
@@ -63,7 +65,9 @@ export type StripInternalTypeSignatures = {
    * @internal
    */
   internalProperty: number;
-  /**@internal */
+  /**
+   * @internal
+   */
   new (): any;
 };
 
@@ -79,4 +83,4 @@ export namespace StripInternalNamespaceInner {
 /**
  * @internal
  */
-export namespace StripInternalNamespace {}
+export namespace StripInternalNamespace {}

crates/oxc_isolated_declarations/tests/fixtures/ts-export-assignment.ts

@@ -1,6 +1,8 @@
 const Res = 0;
 
-/** comment should be a leading comment of the function Foo */
+/**
+ * comment should be a leading comment of the function Foo
+ */
 export = function Foo(): typeof Res {
   return Res;
 };

crates/oxc_isolated_declarations/tests/snapshots/class-decorator.snap

@@ -6,11 +6,15 @@ input_file: crates/oxc_isolated_declarations/tests/fixtures/class-decorator.ts
 ==================== .D.TS ====================
 
 export declare class Test1 {
-	/** This method will trigger the feature highlight dialog load/show based on dialogId and analyticsId */
+	/**
+	* This method will trigger the feature highlight dialog load/show based on dialogId and analyticsId
+	*/
 	property: (() => any) | undefined;
 }
 export declare class Test2 {
-	/** This method will trigger the feature highlight dialog load/show based on dialogId and analyticsI */
+	/**
+	* This method will trigger the feature highlight dialog load/show based on dialogId and analyticsI
+	*/
 	property: ((arg: any) => any) | undefined;
 }
 export declare class Test3 {

crates/oxc_isolated_declarations/tests/snapshots/class.snap

@@ -21,17 +21,29 @@ export declare abstract class Qux {
 	baz(): void;
 }
 export declare class Baz {
-	/** Just a comment */
+	/**
+	* Just a comment
+	*/
 	readonly prop1 = "some string";
-	/** Just a comment */
+	/**
+	* Just a comment
+	*/
 	prop2: string;
-	/** Just a comment */
+	/**
+	* Just a comment
+	*/
 	private prop3;
-	/** Just a comment */
+	/**
+	* Just a comment
+	*/
 	private prop4;
-	/** Just a comment */
+	/**
+	* Just a comment
+	*/
 	private static prop5;
-	/** Just a comment */
+	/**
+	* Just a comment
+	*/
 	private static prop6;
 }
 export declare class Boo {
@@ -114,20 +126,20 @@ export declare class PrivateConstructorWithDefaultParameters {
 
   x TS9038: Computed property names on class or object literals cannot be
   | inferred with --isolatedDeclarations.
-    ,-[69:14]
- 68 |   public get badGetter() {
- 69 |     return {[('x')]: 1};
+    ,-[81:14]
+ 80 |   public get badGetter() {
+ 81 |     return {[('x')]: 1};
     :              ^^^^^
- 70 |   }
+ 82 |   }
     `----
 
   x TS9011: Parameter must have an explicit type annotation with
   | --isolatedDeclarations.
-    ,-[67:14]
- 66 | export class PublicMethodClass {
- 67 |   public bad(a): void {}
+    ,-[79:14]
+ 78 | export class PublicMethodClass {
+ 79 |   public bad(a): void {}
     :              ^
- 68 |   public get badGetter() {
+ 80 |   public get badGetter() {
     `----
 
 

crates/oxc_isolated_declarations/tests/snapshots/export-default.snap

@@ -5,7 +5,9 @@ input_file: crates/oxc_isolated_declarations/tests/fixtures/export-default.ts
 ```
 ==================== .D.TS ====================
 
-/** comment should be a leading comment of the class */
+/**
+* comment should be a leading comment of the class
+*/
 export default class Tokenizer {
 	delimiterClose: Uint8Array;
 }

crates/oxc_isolated_declarations/tests/snapshots/export-default2.snap

@@ -5,6 +5,8 @@ input_file: crates/oxc_isolated_declarations/tests/fixtures/export-default2.ts
 ```
 ==================== .D.TS ====================
 
-/** comment should be a leading comment of the arrow function */
+/**
+* comment should be a leading comment of the arrow function
+*/
 declare const _default: () => number;
 export default _default;

crates/oxc_isolated_declarations/tests/snapshots/ts-export-assignment.snap

@@ -6,6 +6,8 @@ input_file: crates/oxc_isolated_declarations/tests/fixtures/ts-export-assignment
 ==================== .D.TS ====================
 
 declare const Res = 0;
-/** comment should be a leading comment of the function Foo */
+/**
+* comment should be a leading comment of the function Foo
+*/
 declare const _default: () => typeof Res;
 export = _default;