perf(es/parser): Reduce string comparison (#10355)

bvanjoi · web-flow · commit 21789c407795 · 2025-04-11T14:02:33.000+09:00
diff --git a/.changeset/healthy-planes-behave.md b/.changeset/healthy-planes-behave.md
@@ -0,0 +1,6 @@
+---
+swc_core: patch
+swc_ecma_parser: patch
+---
+
+perf(es/parser): less str cmp
diff --git a/crates/swc_ecma_parser/src/parser/ident.rs b/crates/swc_ecma_parser/src/parser/ident.rs
@@ -159,8 +159,7 @@ impl<I: Tokens> Parser<I> {
                 Word::Keyword(Keyword::This) if p.input.syntax().typescript() => Ok(atom!("this")),
                 Word::Keyword(Keyword::Let) => Ok(atom!("let")),
                 Word::Ident(ident) => {
-                    if matches!(&ident, IdentLike::Other(arguments) if &**arguments == "arguments")
-                        && p.ctx().in_class_field
+                    if p.ctx().in_class_field && matches!(&ident, IdentLike::Other(arguments) if atom!("arguments").eq(arguments))
                     {
                         p.emit_err(p.input.prev_span(), SyntaxError::ArgumentsInClassField)
                     }

Original file line number	Diff line number	Diff line change
`@@ -159,8 +159,7 @@ impl<I: Tokens> Parser<I> {`
`159`	`159`	`Word::Keyword(Keyword::This) if p.input.syntax().typescript() => Ok(atom!("this")),`
`160`	`160`	`Word::Keyword(Keyword::Let) => Ok(atom!("let")),`
`161`	`161`	`Word::Ident(ident) => {`
`162`		`- if matches!(&ident, IdentLike::Other(arguments) if &**arguments == "arguments")`
`163`		`- && p.ctx().in_class_field`
	`162`	`+ if p.ctx().in_class_field && matches!(&ident, IdentLike::Other(arguments) if atom!("arguments").eq(arguments))`
`164`	`163`	`{`
`165`	`164`	`p.emit_err(p.input.prev_span(), SyntaxError::ArgumentsInClassField)`
`166`	`165`	`}`