fix: add Primitive to Serializable (#1596)

Co-authored-by: Adam Skoufis <[email protected]>
Co-authored-by: Adam Skoufis <[email protected]>

Author: cqh963852

.changeset/gentle-timers-rescue.md

@@ -0,0 +1,5 @@
+---
+'@vanilla-extract/css': patch
+---
+
+`addFunctionSerializer`: Fix `args` type to support arrays of primitive values

packages/css/src/functionSerializer.ts

@@ -1,6 +1,7 @@
 type Primitive = string | number | boolean | null | undefined;
 
 type Serializable =
+  | Primitive
   | {
       [Key in string | number]: Primitive | Serializable;
     }

packages/integration/src/processVanillaFile.test.ts

@@ -1,3 +1,4 @@
+import { addFunctionSerializer } from '../../css/src/functionSerializer';
 import { serializeVanillaModule } from './processVanillaFile';
 
 describe('serializeVanillaModule', () => {
@@ -138,6 +139,28 @@ describe('serializeVanillaModule', () => {
     `);
   });
 
+  test('should handle deprecated __recipe__ function serialization', () => {
+    const sprinkles = () => {};
+    // Once support for `__recipe__` is removed, this test can be removed,
+    // and all other tests that use `__function_serializer__` should be updated
+    // to use `addFunctionSerializer`
+    addFunctionSerializer(sprinkles, {
+      importPath: 'my-package',
+      importName: 'myFunction',
+      args: ['arg1', 'arg2'],
+    });
+    const exports = {
+      sprinkles,
+    };
+
+    expect(serializeVanillaModule(['import "./styles.css"'], exports, null))
+      .toMatchInlineSnapshot(`
+      "import "./styles.css"
+      import { myFunction as _86bce } from 'my-package';
+      export var sprinkles = _86bce('arg1','arg2');"
+    `);
+  });
+
   test('should re-use exports in handle serialized function args', () => {
     const complexExport = {
       my: {