Add compat data for ::part

Fixes parcel-bundler#515

Author: devongovett

scripts/build-prefixes.js

@@ -307,6 +307,7 @@ let mdnFeatures = {
         }
       })
   ),
+  partPseudo: mdn.css.selectors.part.__compat.support,
   imageSet: mdn.css.types.image['image-set'].__compat.support,
   xResolutionUnit: mdn.css.types.resolution.x.__compat.support,
   nthChildOf: mdn.css.selectors['nth-child'].of_syntax.__compat.support,

src/compat.rs

@@ -122,6 +122,7 @@ pub enum Feature {
   OriyaListStyleType,
   OverflowShorthand,
   P3Colors,
+  PartPseudo,
   PersianListStyleType,
   PlaceContent,
   PlaceItems,
@@ -2500,6 +2501,51 @@ impl Feature {
           return false;
         }
       }
+      Feature::PartPseudo => {
+        if let Some(version) = browsers.chrome {
+          if version < 4784128 {
+            return false;
+          }
+        }
+        if let Some(version) = browsers.edge {
+          if version < 5177344 {
+            return false;
+          }
+        }
+        if let Some(version) = browsers.firefox {
+          if version < 5177344 {
+            return false;
+          }
+        }
+        if let Some(version) = browsers.opera {
+          if version < 3407872 {
+            return false;
+          }
+        }
+        if let Some(version) = browsers.safari {
+          if version < 852224 {
+            return false;
+          }
+        }
+        if let Some(version) = browsers.ios_saf {
+          if version < 852992 {
+            return false;
+          }
+        }
+        if let Some(version) = browsers.samsung {
+          if version < 720896 {
+            return false;
+          }
+        }
+        if let Some(version) = browsers.android {
+          if version < 4784128 {
+            return false;
+          }
+        }
+        if browsers.ie.is_some() {
+          return false;
+        }
+      }
       Feature::ImageSet => {
         if let Some(version) = browsers.chrome {
           if version < 1638400 {

src/lib.rs

@@ -9556,7 +9556,25 @@ mod tests {
       Browsers {
         safari: Some(12 << 16),
         ..Browsers::default()
-      }.into(),
+      }
+      .into(),
+    );
+
+    prefix_test(
+      r#"
+      .foo::part(header), .foo::part(body) {
+        display: none
+      }
+      "#,
+      indoc! {r#"
+      .foo::part(header), .foo::part(body) {
+        display: none;
+      }
+      "#},
+      Browsers {
+        safari: Some(14 << 16),
+        ..Browsers::default()
+      },
     );
   }
 

src/selector.rs

@@ -1746,7 +1746,7 @@ pub(crate) fn is_compatible(selectors: &[Selector], targets: Targets) -> bool {
 
         Component::Scope | Component::Host(_) | Component::Slotted(_) => Feature::Shadowdomv1,
 
-        Component::Part(_) => return false, // TODO: find this data in caniuse-lite
+        Component::Part(_) => Feature::PartPseudo,
 
         Component::NonTSPseudoClass(pseudo) => {
           match pseudo {