Fix iOS markdown style metadata warnings

Resolve markdown UITextView styles to plain React Native text styles before crossing the third-party boundary. react-native-uitextview flattens parent and child styles internally, so Unistyles metadata must not be carried into that handoff.
2026-06-05 19:11:29 +07:00
parent 45cca8a406
commit abf129f56e
3 changed files with 66 additions and 2 deletions
@@ -0,0 +1,32 @@
+import { describe, expect, it } from "vitest";
+import { StyleSheet, type TextStyle } from "react-native";
+import { resolvePlainMarkdownTextStyle } from "@/components/markdown-text-style";
+
+function unistylesStyle(id: string, style: Record<string, unknown>) {
+  return {
+    ...style,
+    [`unistyles_${id}`]: { id },
+  };
+}
+
+function uiTextViewFlatten(rootStyle: TextStyle, style: TextStyle): Record<string, unknown> {
+  // react-native-uitextview/src/util.ts:8 flattens [rootStyle, style]
+  // before passing the result to its native View-backed components.
+  return { ...(StyleSheet.flatten([rootStyle, style]) as Record<string, unknown>) };
+}
+
+function unistylesMetadataKeys(style: Record<string, unknown>) {
+  return Object.keys(style).filter((key) => key.startsWith("unistyles_"));
+}
+
+describe("resolvePlainMarkdownTextStyle", () => {
+  it("keeps UITextView from collapsing parent and child Unistyles styles into one native View style object", () => {
+    const merged = uiTextViewFlatten(
+      resolvePlainMarkdownTextStyle(unistylesStyle("paragraph", { color: "#111" })),
+      resolvePlainMarkdownTextStyle(unistylesStyle("text", { fontWeight: "600" })),
+    );
+
+    expect(unistylesMetadataKeys(merged)).toHaveLength(0);
+    expect(merged).toMatchObject({ color: "#111", fontWeight: "600" });
+  });
+});