Gracefully handle empty "xstyle" prop values (#23190)

packages/react-devtools-shared/src/backend/StyleX/__tests__/utils-test.js

@@ -33,6 +33,29 @@ describe('Stylex plugin utils', () => {
     });
   });
 
+  it('should gracefully handle empty values', () => {
+    expect(getStyleXData(null)).toMatchInlineSnapshot(`
+      Object {
+        "resolvedStyles": Object {},
+        "sources": Array [],
+      }
+    `);
+
+    expect(getStyleXData(undefined)).toMatchInlineSnapshot(`
+      Object {
+        "resolvedStyles": Object {},
+        "sources": Array [],
+      }
+    `);
+
+    expect(getStyleXData('')).toMatchInlineSnapshot(`
+      Object {
+        "resolvedStyles": Object {},
+        "sources": Array [],
+      }
+    `);
+  });
+
   it('should support simple style objects', () => {
     defineStyles(`
       .foo {

packages/react-devtools-shared/src/backend/StyleX/utils.js

@@ -29,6 +29,10 @@ export function crawlData(
   sources: Set<string>,
   resolvedStyles: Object,
 ): void {
+  if (data == null) {
+    return;
+  }
+
   if (isArray(data)) {
     data.forEach(entry => {
       if (isArray(entry)) {