perf(css-vars): remove empty selector regex

Author: adamdbradley

src/client/polyfills/css-shim/regex.ts

@@ -4,4 +4,3 @@ export const VAR_ASSIGN_START = /\B--[\w-]+\s*:/;
 
 export const COMMENTS = /\/\*[^*]*\*+([^/*][^*]*\*+)*\//gim;
 export const TRAILING_LINES = /^[\t ]+\n/gm;
-export const EMPTY_SELECTORS = /[^{}]*{\s*}/gm;

src/client/polyfills/css-shim/template.ts

@@ -1,6 +1,6 @@
 import { findRegex } from './utils';
 import { CSSTemplate, CSSVariables } from './interfaces';
-import { COMMENTS, EMPTY_SELECTORS, TRAILING_LINES, VAR_ASSIGN_START, VAR_USAGE_START } from './regex';
+import { COMMENTS, TRAILING_LINES, VAR_ASSIGN_START, VAR_USAGE_START } from './regex';
 
 
 export function resolveVar(props: CSSVariables, prop: string, fallback: CSSTemplate | undefined): string {
@@ -128,7 +128,6 @@ export function compileTemplate(cssText: string): CSSTemplate {
   cssText = cssText.replace(COMMENTS, '');
 
   cssText = removeCustomAssigns(cssText)
-    .replace(EMPTY_SELECTORS, '')
     .replace(TRAILING_LINES, '');
 
   const segments: CSSTemplate = [];

src/client/polyfills/css-shim/test/css-shim.spec.ts

@@ -231,6 +231,7 @@ describe('css-shim', () => {
 
     expect(css(styleElm.innerHTML)).toBe(
       css(`
+        html{}
         p {
           color: red;
         }
@@ -276,6 +277,7 @@ describe('css-shim', () => {
 
     expect(css(styleElm.innerHTML)).toBe(
       css(`
+        html{}
         .transform {
           transform: translate3d(0, 88px, 0);
         }
@@ -301,6 +303,7 @@ describe('css-shim', () => {
 
     expect(css(styleElm.innerHTML)).toBe(
       css(`
+        html{}
         @keyframes animation {
           0% { opacity: 0.3; }
           100% { opacity: 0.8; }
@@ -327,6 +330,7 @@ describe('css-shim', () => {
 
     expect(css(styleElm.innerHTML)).toBe(
       css(`
+        html{}
         @media only screen {
           body {
             color: red;
@@ -358,6 +362,7 @@ describe('css-shim', () => {
 
     expect(css(styleElm.innerHTML)).toBe(
       css(`
+        html{}
         div {
           animation-name: slidein;
           animation-duration: 3s;