perf(ssr): improve isComment check (#6078)

hkk12369 · web-flow · commit 25f7a16a6ecc · 2022-06-12T23:06:15.000-04:00
diff --git a/packages/server-renderer/src/helpers/ssrRenderSlot.ts b/packages/server-renderer/src/helpers/ssrRenderSlot.ts
@@ -87,11 +87,11 @@ export function ssrRenderSlotInner(
   }
 }
 
+const commentTestRE = /^<!--.*-->$/s
 const commentRE = /<!--[^]*?-->/gm
 function isComment(item: SSRBufferItem) {
-  return (
-    typeof item === 'string' &&
-    commentRE.test(item) &&
-    !item.replace(commentRE, '').trim()
-  )
+  if (typeof item !== 'string' || !commentTestRE.test(item)) return false
+  // if item is '<!---->' or '<!--[-->' or '<!--]-->', return true directly
+  if (item.length <= 8) return true
+  return !item.replace(commentRE, '').trim()
 }

Original file line number	Diff line number	Diff line change
`@@ -87,11 +87,11 @@ export function ssrRenderSlotInner(`
`87`	`87`	`}`
`88`	`88`	`}`
`89`	`89`
	`90`	`+const commentTestRE = /^<!--.*-->$/s`
`90`	`91`	`const commentRE = /<!--[^]*?-->/gm`
`91`	`92`	`function isComment(item: SSRBufferItem) {`
`92`		`- return (`
`93`		`- typeof item === 'string' &&`
`94`		`- commentRE.test(item) &&`
`95`		`- !item.replace(commentRE, '').trim()`
`96`		`- )`
	`93`	`+ if (typeof item !== 'string' \|\| !commentTestRE.test(item)) return false`
	`94`	`+ // if item is '<!---->' or '<!--[-->' or '<!--]-->', return true directly`
	`95`	`+ if (item.length <= 8) return true`
	`96`	`+ return !item.replace(commentRE, '').trim()`
`97`	`97`	`}`