feat(css/parser): normalize at-rule name

crates/swc_css_codegen/tests/fixture.rs

@@ -113,14 +113,6 @@ fn run(input: &Path, minify: bool) {
 struct NormalizeTest;
 
 impl VisitMut for NormalizeTest {
-    fn visit_mut_at_rule(&mut self, n: &mut AtRule) {
-        n.visit_mut_children_with(self);
-
-        if let AtRuleName::Ident(ident) = &mut n.name {
-            ident.value = ident.value.to_lowercase().into();
-        }
-    }
-
     fn visit_mut_media_query(&mut self, n: &mut MediaQuery) {
         n.visit_mut_children_with(self);
 

crates/swc_css_compat/src/compiler/custom_media.rs

@@ -18,7 +18,7 @@ pub(super) struct CustomMediaHandler {
 impl CustomMediaHandler {
     pub(crate) fn store_custom_media(&mut self, n: &mut AtRule) {
         if let AtRuleName::Ident(name) = &n.name {
-            if name.value.eq_ignore_ascii_case(&js_word!("custom-media")) {
+            if name.value == js_word!("custom-media") {
                 if let Some(box AtRulePrelude::CustomMediaPrelude(prelude)) = &mut n.prelude {
                     self.medias.push(prelude.take());
                 }
@@ -29,7 +29,7 @@ impl CustomMediaHandler {
     pub(crate) fn process_rules(&mut self, n: &mut Vec<Rule>) {
         n.retain(|n| match n {
             Rule::AtRule(n) => {
-                if matches!(&n.name, AtRuleName::Ident(ident) if ident.value.eq_ignore_ascii_case(&js_word!("custom-media"))) {
+                if matches!(&n.name, AtRuleName::Ident(ident) if ident.value == js_word!("custom-media")) {
                     return false;
                 }
 

crates/swc_css_minifier/src/compressor/rules.rs

@@ -53,8 +53,8 @@ impl Visit for CompatibilityChecker {
 impl Compressor {
     fn get_at_rule_name(&self, at_rule: &AtRule) -> JsWord {
         match &at_rule.name {
-            AtRuleName::Ident(Ident { value, .. }) => value.to_ascii_lowercase(),
-            AtRuleName::DashedIdent(DashedIdent { value, .. }) => value.to_ascii_lowercase(),
+            AtRuleName::Ident(Ident { value, .. }) => value.clone(),
+            AtRuleName::DashedIdent(DashedIdent { value, .. }) => value.clone(),
         }
     }
 
@@ -329,13 +329,13 @@ impl Compressor {
             _ => return false,
         };
 
-        matches_eq_ignore_ascii_case!(
-            name,
-            js_word!("media"),
-            js_word!("supports"),
-            js_word!("container"),
-            js_word!("layer"),
-            js_word!("nest")
+        matches!(
+            *name,
+            js_word!("media")
+                | js_word!("supports")
+                | js_word!("container")
+                | js_word!("layer")
+                | js_word!("nest")
         )
     }
 
@@ -643,6 +643,7 @@ impl Compressor {
     }
 }
 
+#[inline]
 fn need_keep_by_name(name: &JsWord) -> bool {
-    matches_eq_ignore_ascii_case!(name, js_word!("color-profile"))
+    *name == js_word!("color-profile")
 }

crates/swc_css_parser/src/parser/syntax/mod.rs

@@ -148,16 +148,17 @@ where
                 unreachable!()
             }
         };
-        let name = if at_keyword_name.0.starts_with("--") {
+        let is_dashed_ident = at_keyword_name.0.starts_with("--");
+        let name = if is_dashed_ident {
             AtRuleName::DashedIdent(DashedIdent {
                 span: Span::new(span.lo + BytePos(1), span.hi, Default::default()),
-                value: at_keyword_name.0,
+                value: at_keyword_name.0[2..].into(),
                 raw: Some(at_keyword_name.1),
             })
         } else {
             AtRuleName::Ident(Ident {
                 span: Span::new(span.lo + BytePos(1), span.hi, Default::default()),
-                value: at_keyword_name.0,
+                value: at_keyword_name.0.to_ascii_lowercase(),
                 raw: Some(at_keyword_name.1),
             })
         };

crates/swc_css_parser/tests/fixture/at-rule/import/output.json

@@ -272,7 +272,7 @@
           "end": 136,
           "ctxt": 0
         },
-        "value": "IMPORT",
+        "value": "import",
         "raw": "IMPORT"
       },
       "prelude": {
@@ -2016,7 +2016,7 @@
           "end": 904,
           "ctxt": 0
         },
-        "value": "IMPORT",
+        "value": "import",
         "raw": "IMPORT"
       },
       "prelude": {

crates/swc_css_parser/tests/fixture/at-rule/supports/output.json

@@ -825,7 +825,7 @@
           "end": 330,
           "ctxt": 0
         },
-        "value": "SUPPORTS",
+        "value": "supports",
         "raw": "SUPPORTS"
       },
       "prelude": {

crates/swc_css_parser/tests/fixture/dashed-ident/output.json

@@ -456,7 +456,7 @@
           "end": 146,
           "ctxt": 0
         },
-        "value": "--custom",
+        "value": "custom",
         "raw": "--custom"
       },
       "prelude": {
@@ -515,7 +515,7 @@
           "end": 168,
           "ctxt": 0
         },
-        "value": "--library1-custom",
+        "value": "library1-custom",
         "raw": "--library1-custom"
       },
       "prelude": {

crates/swc_css_prefixer/src/prefixer.rs

@@ -743,9 +743,7 @@ impl VisitMut for Prefixer {
         at_rule.visit_mut_children_with(self);
 
         match &at_rule.name {
-            AtRuleName::Ident(Ident { span, value, .. })
-                if value.as_ref().eq_ignore_ascii_case("viewport") =>
-            {
+            AtRuleName::Ident(Ident { span, value, .. }) if value == "viewport" => {
                 if should_prefix("@-o-viewport", self.env, false) {
                     self.add_at_rule(
                         Prefix::Ms,
@@ -778,9 +776,7 @@ impl VisitMut for Prefixer {
                     );
                 }
             }
-            AtRuleName::Ident(Ident { span, value, .. })
-                if value.as_ref().eq_ignore_ascii_case("keyframes") =>
-            {
+            AtRuleName::Ident(Ident { span, value, .. }) if value == "keyframes" => {
                 if should_prefix("@-webkit-keyframes", self.env, false) {
                     self.add_at_rule(
                         Prefix::Webkit,