Perf: don't run the regex replace unless the selectorText contains a colon (#1280)

* Perf: don't run the regex replace unless the selectorText contains a colon (rules generally contain colons)

* Need to check type before querying selectorText property - also good as it means we only try to fix colons at the leaf level
---------

Authored-by: eoghan murray <eoghan@getthere.ie>

packages/rrweb-snapshot/src/snapshot.ts

@@ -22,7 +22,6 @@ import {
   stringifyStylesheet,
   getInputType,
   toLowerCase,
-  validateStringifiedCssRule,
 } from './utils';
 
 let _id = 1;

packages/rrweb-snapshot/src/utils.ts

@@ -119,26 +119,29 @@ export function stringifyRule(rule: CSSRule): string {
     } catch (error) {
       // ignore
     }
-  }
-
-  return validateStringifiedCssRule(importStringified || rule.cssText);
-}
-
-export function validateStringifiedCssRule(cssStringified: string): string {
+  } else if (isCSSStyleRule(rule) && rule.selectorText.includes(':')) {
     // Safari does not escape selectors with : properly
-  if (cssStringified.includes(':')) {
+    // see https://bugs.webkit.org/show_bug.cgi?id=184604
+    return fixSafariColons(rule.cssText);
+  }
+
+  return importStringified || rule.cssText;
+}
+
+export function fixSafariColons(cssStringified: string): string {
   // Replace e.g. [aa:bb] with [aa\\:bb]
   const regex = /(\[(?:[\w-]+)[^\\])(:(?:[\w-]+)\])/gm;
   return cssStringified.replace(regex, '$1\\$2');
 }
 
-  return cssStringified;
-}
-
 export function isCSSImportRule(rule: CSSRule): rule is CSSImportRule {
   return 'styleSheet' in rule;
 }
 
+export function isCSSStyleRule(rule: CSSRule): rule is CSSStyleRule {
+  return 'selectorText' in rule;
+}
+
 export class Mirror implements IMirror<Node> {
   private idNodeMap: idNodeMap = new Map();
   private nodeMetaMap: nodeMetaMap = new WeakMap();

packages/rrweb-snapshot/test/css.test.ts

@@ -1,8 +1,5 @@
 import { parse, Rule, Media } from '../src/css';
-import {
-  validateStringifiedCssRule,
-  escapeImportStatement,
-} from './../src/utils';
+import { fixSafariColons, escapeImportStatement } from './../src/utils';
 
 describe('css parser', () => {
   it('should save the filename and source', () => {
@@ -112,15 +109,13 @@ describe('css parser', () => {
   });
 
   it('parses : in attribute selectors correctly', () => {
-    const out1 = validateStringifiedCssRule('[data-foo] { color: red; }');
+    const out1 = fixSafariColons('[data-foo] { color: red; }');
     expect(out1).toEqual('[data-foo] { color: red; }');
 
-    const out2 = validateStringifiedCssRule('[data-foo:other] { color: red; }');
+    const out2 = fixSafariColons('[data-foo:other] { color: red; }');
     expect(out2).toEqual('[data-foo\\:other] { color: red; }');
 
-    const out3 = validateStringifiedCssRule(
-      '[data-aa\\:other] { color: red; }',
-    );
+    const out3 = fixSafariColons('[data-aa\\:other] { color: red; }');
     expect(out3).toEqual('[data-aa\\:other] { color: red; }');
   });
 

yarn.lock

@@ -5522,15 +5522,10 @@ csso@^4.0.2:
   dependencies:
     css-tree "^1.1.2"
 
-cssom@^0.4.4, "cssom@https://registry.npmjs.org/rrweb-cssom/-/rrweb-cssom-0.6.0.tgz":
+cssom@^0.4.4, cssom@^0.5.0, "cssom@https://registry.npmjs.org/rrweb-cssom/-/rrweb-cssom-0.6.0.tgz":
   version "0.6.0"
   resolved "https://registry.npmjs.org/rrweb-cssom/-/rrweb-cssom-0.6.0.tgz#ed298055b97cbddcdeb278f904857629dec5e0e1"
 
-cssom@^0.5.0:
-  version "0.5.0"
-  resolved "https://registry.yarnpkg.com/cssom/-/cssom-0.5.0.tgz#d254fa92cd8b6fbd83811b9fbaed34663cc17c36"
-  integrity sha512-iKuQcq+NdHqlAcwUY0o/HL69XQrUaQdMjmStJ8JFmUaiiQErlhrmuigkg/CU4E2J0IyUKUrMAgl36TvN67MqTw==
-
 cssom@~0.3.6:
   version "0.3.8"
   resolved "https://registry.yarnpkg.com/cssom/-/cssom-0.3.8.tgz#9f1276f5b2b463f2114d3f2c75250af8c1a36f4a"