ios wkwebview 清除缓存

if ([[[UIDevice currentDevice]systemVersion]intValue ] >8) {
NSArray * types =@[WKWebsiteDataTypeMemoryCache,WKWebsiteDataTypeDiskCache]; // 9.0之后才有的
NSSet *websiteDataTypes = [NSSet setWithArray:types];
NSDate *dateFrom = [NSDate dateWithTimeIntervalSince1970:0];

    [[WKWebsiteDataStore defaultDataStore] removeDataOfTypes:websiteDataTypes modifiedSince: dateFrom completionHandler:^{
    
    }];
}else{
    NSString *libraryPath = [NSSearchPathForDirectoriesInDomains(NSLibraryDirectory,NSUserDomainMask,YES) objectAtIndex:0];
    
    NSString *cookiesFolderPath = [libraryPath stringByAppendingString:@"/Cookies"];

    NSError *errors;
    [[NSFileManager defaultManager] removeItemAtPath:cookiesFolderPath error:&errors];
}