fix: #23 this.pre is undefined cause error

Zippowxk · Zippowxk · commit 0e883eb7d28e · 2021-11-08T09:54:11.000+08:00
diff --git a/src/helper.js b/src/helper.js
@@ -161,7 +161,7 @@ export default class VueRouterKeepAliveHelper{
       this.replaceStay.includes(this.replacePrePath)
     );
     if (shouldDestroy) {
-      this.pre.$keepAliveDestroy();
+      this.pre?.$keepAliveDestroy();
     }
     this.setState(this.stackPointer);
     this.historyStack.push(vm, this.stackPointer);

Original file line number	Diff line number	Diff line change
`@@ -161,7 +161,7 @@ export default class VueRouterKeepAliveHelper{`
`161`	`161`	`this.replaceStay.includes(this.replacePrePath)`
`162`	`162`	`);`
`163`	`163`	`if (shouldDestroy) {`
`164`		`- this.pre.$keepAliveDestroy();`
	`164`	`+ this.pre?.$keepAliveDestroy();`
`165`	`165`	`}`
`166`	`166`	`this.setState(this.stackPointer);`
`167`	`167`	`this.historyStack.push(vm, this.stackPointer);`