fix: line-height parsing (#27)

Author: marklawlor

example/global.css

@@ -1,3 +1,20 @@
 @import "tailwindcss/theme.css" layer(theme);
 @import "tailwindcss/preflight.css" layer(base);
-@import "tailwindcss/utilities.css"; 
+@import "tailwindcss/utilities.css"; 
+
+@theme {
+  --text-xs--line-height: calc(1em / 0.75);
+  --text-sm--line-height: calc(1.25em / 0.875);
+  --text-base--line-height: calc(1.5em / 1);
+  --text-lg--line-height: calc(1.75em / 1.125);
+  --text-xl--line-height: calc(1.75em / 1.25);
+  --text-2xl--line-height: calc(2em / 1.5);
+  --text-3xl--line-height: calc(2.25em / 1.875);
+  --text-4xl--line-height: calc(2.5em / 2.25);
+
+  --leading-tight: 1.25em;
+  --leading-snug: 1.375em;
+  --leading-normal: 1.5em;
+  --leading-relaxed: 1.625em;
+  --leading-loose: 2em;
+}

example/src/App.tsx

@@ -6,9 +6,7 @@ export default function App() {
   return (
     <>
       <View className="justify-center items-center h-full">
-        <Text className="text-green-500 ring-2 ring-blue-500 shadow-xl shadow-red-500">
-          Test Component
-        </Text>
+        <Text className="text-red-500">Test Component</Text>
       </View>
     </>
   );

src/compiler/declarations.ts

@@ -57,7 +57,7 @@ const propertyRename: Record<string, string> = {
   "background-image": "experimental_backgroundImage",
 };
 
-const needsRuntimeParsing = new Set([
+const unparsedRuntimeParsing = new Set([
   "animation",
   "text-shadow",
   "transform",
@@ -811,7 +811,7 @@ export function parseDeclarationUnparsed(
   /**
    * Unparsed shorthand properties need to be parsed at runtime
    */
-  if (needsRuntimeParsing.has(property)) {
+  if (unparsedRuntimeParsing.has(property)) {
     const args = parseUnparsed(declaration.value.value, builder);
 
     if (property === "animation") {
@@ -829,10 +829,13 @@ export function parseDeclarationUnparsed(
       ]);
     }
   } else {
-    builder.addDescriptor(
-      property,
-      parseUnparsed(declaration.value.value, builder),
-    );
+    const value = parseUnparsed(declaration.value.value, builder);
+
+    builder.addDescriptor(property, value);
+
+    if (property === "font-size") {
+      builder.addDescriptor("--__rn-css-em", value);
+    }
   }
 }