fix: handle prefixing paths that start with numbers

packages/core/src/form.test.ts

@@ -38,3 +38,49 @@ it("should be able to nest scopes arbitrarily deep", () => {
   const baz = bar.scope("baz");
   expect(baz.__field_prefix__).toBe("foo.bar.baz");
 });
+
+it("should be able to nest scopes with arrays", () => {
+  const form = createFormScope({
+    defaultValues: {
+      foo: {
+        bar: [
+          {
+            baz: "baz",
+          },
+        ],
+      },
+    },
+    serverValidationErrors: {},
+    validator: createValidator({
+      validate: (data) => Promise.resolve({ data, error: undefined }),
+    }),
+    submitSource: "state",
+    onSubmit: vi.fn(),
+    onSubmitSuccess: vi.fn(),
+    onSubmitFailure: vi.fn(),
+    onBeforeSubmit: vi.fn(),
+    onInvalidSubmit: vi.fn(),
+    flags: {
+      disableFocusOnError: false,
+      reloadDocument: false,
+    },
+    formProps: { id: "test-form" },
+  });
+
+  expect(form.__field_prefix__).toBe("");
+
+  const foo = form.scope("foo");
+  expect(foo.__field_prefix__).toBe("foo");
+
+  const bar = foo.scope("bar");
+  expect(bar.__field_prefix__).toBe("foo.bar");
+
+  const item = bar.scope("0");
+  expect(item.__field_prefix__).toBe("foo.bar[0]");
+
+  const baz = item.scope("baz");
+  expect(baz.__field_prefix__).toBe("foo.bar[0].baz");
+
+  const itemBaz = bar.scope("0.baz");
+  expect(itemBaz.__field_prefix__).toBe("foo.bar[0].baz");
+});

packages/core/src/form.ts

@@ -25,6 +25,7 @@ import {
   ValidStringPaths,
   ValueAtPath,
   pathArrayToString,
+  stringToPathArray,
 } from "@rvf/set-get";
 
 type SubmitTypes<FormOutputData> =
@@ -143,7 +144,11 @@ const instantiateFormScope = <FormInputData extends FieldValues>(
   __field_prefix__: prefix,
   __store__: store,
   scope(field) {
-    const newPrefix = pathArrayToString([prefix, field].filter(Boolean));
+    const newPrefix = pathArrayToString(
+      [...stringToPathArray(prefix), ...stringToPathArray(field)].filter(
+        (segment) => segment !== "",
+      ),
+    );
     if (store.subformCache.has(newPrefix))
       return store.subformCache.get(newPrefix);