无法将 Javascript 加载到 WKWebView 原因：“数据参数为零”

如何解决无法将 Javascript 加载到 WKWebView 原因：“数据参数为零”

我有这样的 Objective-C 代码：

#import "QHArticle.h"
#import <WebKit/WebKit.h>

-(instancetype)init
{
    self = [super init];
    if (self)
    {
        _helperWebView = [[WKWebView alloc] init];
        Nsstring *path = [[NSBundle mainBundle] pathForResource:@"Article" ofType:@"js"];
        content = [Nsstring stringWithContentsOfFile:path encoding:NSUTF8StringEncoding error:nil];
        WKUserScript *wkUScript = [[WKUserScript alloc] initWithSource:content injectionTime:WKUserScriptInjectionTimeAtDocumentEnd forMainFrameOnly:YES];
        [_helperWebView.configuration.userContentController addUserScript:wkUScript];
        [_helperWebView reload];
    }
    return self;
}


- (Nsstring *)callJSMethod:(Nsstring *)method
{
    __block Nsstring *resultString = nil;
    __block BOOL finished = NO;
    [_helperWebView evaluateJavaScript:method completionHandler:^(id result,NSError *error) {
        if (error == nil) {
            if (result != nil) {
                resultString = [Nsstring stringWithFormat:@"%@",result];
            }
        } else {
            NSLog(@"evaluateJavaScript error : %@",error.localizedDescription);
        }
        finished = YES;
    }];

    while (!finished)
    {
        [[NSRunLoop currentRunLoop] runMode:NSDefaultRunLoopMode beforeDate:[NSDate distantFuture]];
    }
    return resultString;
}

但是我得到了空白屏幕和错误： 2021-01-18 16:56:57.117808+0700 Q-UII[5400:419080]evaluateJavaScript 错误：发生 JavaScript 异常。由于未捕获的异常“NSinvalidargumentexception”而终止应用程序，原因：“数据参数为零”

请帮忙。