如何解决类型“从不”中不存在的属性

Question

I'm using the library react-google-recaptcha to generate invisible ReCaptcha and I get the follow typescript error:

Property 'execute' does not exist in type 'never'

This is the code:

  const recaptcha = useRef(null);

  useEffect(() => {
    let token;
    if (recaptchaLoaded) {
      token = recaptcha.current?.execute();
    }
  }, [recaptchaLoaded]);
  
  
   <ReCAPTCHA
      ref={recaptcha}
      sitekey={SITE_KEY}
    />

How can I type the.execute() so that this error doesn't happen anymore? Or should I do it another way?

Thanks

Answer 1

You need to tell TypeScript the type of what the ref will refer to by providing a type argument to useRef (since TypeScript can't infer it from the initial value null ). Assuming you're using this npm package , it appears you use the type of the component:

const recaptcha = useRef<ReCAPTCHA>(null);
//                      ^^^^^^^^^^^

Answer 2

More onto this; along with useRef(null) recaptcha const

const recaptcha = useRef<ReCAPTCHA>(null);
//                       ^^^^^^^^^   

in the recaptcha component, add an onChange event as in the below snippet.

  <ReCAPTCHA
    ref={recaptchaRef}
    onChange={handleCaptchaChange}
    sitekey="yourSiteKey"
  />


const handleCaptchaChange = () => {
    if (recaptchaRef.current) {
        const token = recaptchaRef.current.getValue();
        if (token)
            setSaveButtonDisabled(token.length <= 0);
    }
}

note the lines above where you are checking for recaptcha.current (if (recaptchaRef.current)) and check for null token (if (token))

the above will assert the possible null errors