Question

在 React 项目中调用 TypeScript 函数时出现此错误。

const handleLanguageChange = React.useCallback((eventKey: eventKey) => {
          setLanguage(eventKey);
          if(eventKey == "DE")
               setCurrency("€ EUR");
          else if(eventKey == "JP")
               setCurrency("¥ JPY");
          else if(eventKey == "US")
               setCurrency("$ USD");
          else
               setCurrency("£ GBP");
          const language = eventKey;
          changeLang(language);  >> ERROR HERE!
     }, []);

function changeLang(language: string) {
          i18n.changeLanguage(language, (err, t) => {
               if (err) {
                    localeChangeHandlerMetric.setFailure();
               } else {
                    localeChangeHandlerMetric.setSuccess();
               }
               localeChangeMetricsPublisher.publish(localeChangeHandlerMetric);
          });
     }

这是我得到的错误：

src/components/navigation/LanguageNav.tsx:44:22
TS2345: Argument of type 'eventKey' is not assignable to parameter of type 'string'.
  Type 'null' is not assignable to type 'string'.
    42 |                setCurrency("£ GBP");
    43 |           const language = eventKey;
  > 44 |           changeLang(language);
       |                      ^^^^^^^^
    45 |      }, []);
    46 | 
    47 |      function changeLang(language: string) {

知道我该如何处理吗？我尝试向 eventKey 添加可选类型，但没有成功。

Answer 1

你 changeLang(language: string) 接收语言作为字符串类型。但是您将语言作为 eventKey 类型传递。你可以做的一些选择

选项 1： 更改 eventKey 的类型

const handleLanguageChange = React.useCallback((eventKey: string) => {
          setLanguage(eventKey);
          if(eventKey == "DE")
               setCurrency("€ EUR");
          else if(eventKey == "JP")
               setCurrency("¥ JPY");
          else if(eventKey == "US")
               setCurrency("$ USD");
          else
               setCurrency("£ GBP");
          const language = eventKey;
          changeLang(language);  
     }, []);

选项 2：使用“as”关键字输入断言

const handleLanguageChange = React.useCallback((eventKey: eventKey) => {
          setLanguage(eventKey);
          if(eventKey == "DE")
               setCurrency("€ EUR");
          else if(eventKey == "JP")
               setCurrency("¥ JPY");
          else if(eventKey == "US")
               setCurrency("$ USD");
          else
               setCurrency("£ GBP");
          const language = eventKey as unknown as string;
          changeLang(language); 
     }, []);

选项 3：忽略它

const handleLanguageChange = React.useCallback((eventKey: eventKey) => {
          setLanguage(eventKey);
          if(eventKey == "DE")
               setCurrency("€ EUR");
          else if(eventKey == "JP")
               setCurrency("¥ JPY");
          else if(eventKey == "US")
               setCurrency("$ USD");
          else
               setCurrency("£ GBP");
          const language = eventKey;
          //@ts-ignore
          changeLang(language); 
     }, []);

“eventKey”类型的参数不能分配给“string”类型的参数。类型 'null' 不能分配给类型 'string'

1 个答案: