feat: 增加暗黑模式的监听，优化产物体积

Author: heiazu

__test__/fixure/style.bin

@@ -8,4 +8,4 @@ Generated by [AVA](https://avajs.dev).
 
 > Snapshot 1
 
-    '{"fonts":[],"keyframes":[],"medias":[],"styles":[{"declarations":[[66,100],[69,"100px"],[67,"100px"],[68,"100px"]],"has_env":false,"media":0,"selector":["px"],"variables":{}}]}'
+    '{"fonts":[],"keyframes":[],"medias":[],"styles":[{"declarations":[[66,100],[69,"100px"],[67,"100px"],[68,"100px"]],"media":0,"selector":["px"]}]}'

__test__/index.spec.mjs.md

@@ -116,8 +116,19 @@ impl JsonWriter {
                 span: DUMMY_SP,
                 elems: parse_style_values(rule_item.declarations.clone(), Platform::Harmony),
               })),
-            }))),
-            PropOrSpread::Prop(Box::new(Prop::KeyValue(KeyValueProp {
+            })))
+          ];
+          if rule_item.has_env {
+            lit_props.push(
+              PropOrSpread::Prop(Box::new(Prop::KeyValue(KeyValueProp {
+                key: PropName::Ident(Ident::new("has_env".into(), DUMMY_SP)),
+                value: Box::new(Expr::Lit(Lit::Bool(Bool { span: DUMMY_SP, value: rule_item.has_env }))),
+              })))
+            );
+          }
+          if rule_item.variables.len() > 0 {
+            lit_props.push(
+              PropOrSpread::Prop(Box::new(Prop::KeyValue(KeyValueProp {
                 key: PropName::Ident(Ident::new("variables".into(), DUMMY_SP)),
                 value: Box::new(Expr::Object(ObjectLit {
                     span: DUMMY_SP,
@@ -132,12 +143,9 @@ impl JsonWriter {
                         })))
                     }).collect::<Vec<PropOrSpread>>()
                 }))
-            }))),
-            PropOrSpread::Prop(Box::new(Prop::KeyValue(KeyValueProp {
-              key: PropName::Ident(Ident::new("has_env".into(), DUMMY_SP)),
-              value: Box::new(Expr::Lit(Lit::Bool(Bool { span: DUMMY_SP, value: rule_item.has_env }))),
-            })))
-          ];
+              })))
+            );
+          }
 
           if pseudo_key.len() > 0 {
             let mut pseudo_enum = None;

__test__/index.spec.mjs.snap

@@ -25,6 +25,7 @@ pub enum StyleMediaFeatureID {
   DeviceHeight = 7,
   DeviceAspectRatio = 8,
   Resolution = 9,
+  PrefersColorScheme = 10,
 }
 
 #[derive(Debug, Clone)]
@@ -383,6 +384,7 @@ impl StyleMedia {
         MediaFeatureId::DeviceHeight => return StyleMediaFeatureID::DeviceHeight,
         MediaFeatureId::DeviceAspectRatio => return StyleMediaFeatureID::DeviceAspectRatio,
         MediaFeatureId::Resolution => return StyleMediaFeatureID::Resolution,
+        MediaFeatureId::PrefersColorScheme => return StyleMediaFeatureID::PrefersColorScheme,
         _ => return StyleMediaFeatureID::Invalid,
       },
       _ => return StyleMediaFeatureID::Invalid,