From de23a0926c2583db01e7df5ea9a134f5910f96a1 Mon Sep 17 00:00:00 2001
From: Anton Evzhakov <anton@evz.name>
Date: Sun, 11 Apr 2021 15:19:57 +0300
Subject: [PATCH] fix(core): remove unnecessary spread operators from css and
 cx (#746) (#749)

---
 packages/core/__tests__/cx.test.ts |  7 +++++++
 packages/core/src/css.ts           | 14 +++++++++-----
 packages/core/src/cx.ts            | 10 +++++++---
 3 files changed, 23 insertions(+), 8 deletions(-)
 create mode 100644 packages/core/__tests__/cx.test.ts

diff --git a/packages/core/__tests__/cx.test.ts b/packages/core/__tests__/cx.test.ts
new file mode 100644
index 000000000..97fabff40
--- /dev/null
+++ b/packages/core/__tests__/cx.test.ts
@@ -0,0 +1,7 @@
+import { cx } from '../src';
+
+it('should filter falsy values', () => {
+  expect(cx('1', 'test', false, '2', 0, '', null, undefined, '3')).toBe(
+    '1 test 2 3'
+  );
+});
diff --git a/packages/core/src/css.ts b/packages/core/src/css.ts
index f1af18493..82c977fa8 100644
--- a/packages/core/src/css.ts
+++ b/packages/core/src/css.ts
@@ -1,11 +1,15 @@
 import type { CSSProperties } from './CSSProperties';
 import type { StyledMeta } from './StyledMeta';
 
-export default function css(
-  _strings: TemplateStringsArray,
-  ..._exprs: Array<string | number | CSSProperties | StyledMeta>
-): string {
+type CSS = (
+  strings: TemplateStringsArray,
+  ...exprs: Array<string | number | CSSProperties | StyledMeta>
+) => string;
+
+const css: CSS = () => {
   throw new Error(
     'Using the "css" tag in runtime is not supported. Make sure you have set up the Babel plugin correctly.'
   );
-}
+};
+
+export default css;
diff --git a/packages/core/src/cx.ts b/packages/core/src/cx.ts
index 191554c52..e34fae2d9 100644
--- a/packages/core/src/cx.ts
+++ b/packages/core/src/cx.ts
@@ -1,5 +1,9 @@
 export type ClassName = string | false | void | null | 0;
 
-export default function cx(...classNames: ClassName[]): string {
-  return classNames.filter(Boolean).join(' ');
-}
+type CX = (...classNames: ClassName[]) => string;
+
+const cx: CX = function cx() {
+  return Array.prototype.slice.call(arguments).filter(Boolean).join(' ');
+};
+
+export default cx;