perf: preinitialize typeCheck RegExp (#10990)

SebastianSpeitel · web-flow · commit 2488a6a1e977 · 2021-03-30T11:36:46.000+02:00
diff --git a/src/core/util/props.js b/src/core/util/props.js
@@ -174,13 +174,15 @@ function assertType (value: any, type: Function): {
   }
 }
 
+const functionTypeCheckRE = /^\s*function (\w+)/
+
 /**
  * Use function string name to check built-in types,
  * because a simple equality check will fail when running
  * across different vms / iframes.
  */
 function getType (fn) {
-  const match = fn && fn.toString().match(/^\s*function (\w+)/)
+  const match = fn && fn.toString().match(functionTypeCheckRE)
   return match ? match[1] : ''
 }
 

Original file line number	Diff line number	Diff line change
`@@ -174,13 +174,15 @@ function assertType (value: any, type: Function): {`
`174`	`174`	`}`
`175`	`175`	`}`
`176`	`176`
	`177`	`+const functionTypeCheckRE = /^\s*function (\w+)/`
	`178`	`+`
`177`	`179`	`/**`
`178`	`180`	`* Use function string name to check built-in types,`
`179`	`181`	`* because a simple equality check will fail when running`
`180`	`182`	`* across different vms / iframes.`
`181`	`183`	`*/`
`182`	`184`	`function getType (fn) {`
`183`		`- const match = fn && fn.toString().match(/^\s*function (\w+)/)`
	`185`	`+ const match = fn && fn.toString().match(functionTypeCheckRE)`
`184`	`186`	`return match ? match[1] : ''`
`185`	`187`	`}`
`186`	`188`