Implement basic support for native animation of font size

android/src/main/java/com/horcrux/svg/RenderableViewManager.java

@@ -15,6 +15,7 @@ import android.view.ViewGroup;
 
 import com.facebook.infer.annotation.Assertions;
 import com.facebook.react.bridge.Dynamic;
+import com.facebook.react.bridge.JavaOnlyMap;
 import com.facebook.react.bridge.ReadableArray;
 import com.facebook.react.bridge.ReadableMap;
 import com.facebook.react.uimanager.DisplayMetricsHolder;
@@ -345,6 +346,22 @@ class RenderableViewManager extends ViewGroupManager<VirtualView> {
         public void setFont(GroupView node, @Nullable ReadableMap font) {
             node.setFont(font);
         }
+
+        @ReactProp(name = "fontSize")
+        public void setFontSize(GroupView node, Dynamic fontSize) {
+            JavaOnlyMap map = new JavaOnlyMap();
+            switch (fontSize.getType()) {
+                case Number:
+                    map.putDouble("fontSize", fontSize.asDouble());
+                    break;
+                case String:
+                    map.putString("fontSize", fontSize.asString());
+                    break;
+                default:
+                    return;
+            }
+            node.setFont(map);
+        }
     }
 
 

ios/ViewManagers/RNSVGGroupManager.m

@@ -21,4 +21,16 @@ RCT_EXPORT_MODULE()
 
 RCT_EXPORT_VIEW_PROPERTY(font, NSDictionary)
 
+RCT_CUSTOM_VIEW_PROPERTY(fontSize, id, RNSVGGroup)
+{
+    if ([json isKindOfClass:[NSString class]]) {
+        NSString *stringValue = (NSString *)json;
+        view.font = @{ @"fontSize": stringValue };
+    } else {
+        NSNumber* number = (NSNumber*)json;
+        double num = [number doubleValue];
+        view.font = @{@"fontSize": [NSNumber numberWithDouble:num] };
+    }
+}
+
 @end

ios/ViewManagers/RNSVGTextManager.m

@@ -68,4 +68,16 @@ RCT_CUSTOM_VIEW_PROPERTY(baselineShift, id, RNSVGText)
 RCT_EXPORT_VIEW_PROPERTY(lengthAdjust, NSString)
 RCT_EXPORT_VIEW_PROPERTY(alignmentBaseline, NSString)
 
+RCT_CUSTOM_VIEW_PROPERTY(fontSize, id, RNSVGGroup)
+{
+    if ([json isKindOfClass:[NSString class]]) {
+        NSString *stringValue = (NSString *)json;
+        view.font = @{ @"fontSize": stringValue };
+    } else {
+        NSNumber* number = (NSNumber*)json;
+        double num = [number doubleValue];
+        view.font = @{@"fontSize": [NSNumber numberWithDouble:num] };
+    }
+}
+
 @end

lib/extract/extractText.js

@@ -33,7 +33,7 @@ function parseFontString(font) {
   const isBold = /bold/.exec(match[1]);
   const isItalic = /italic/.exec(match[1]);
   cachedFontObjectsFromString[font] = {
-    fontSize: match[2] || '12',
+    fontSize: match[2] || 12,
     fontWeight: isBold ? 'bold' : 'normal',
     fontStyle: isItalic ? 'italic' : 'normal',
     fontFamily: extractSingleFontFamily(match[3]),