使用 useRef 和 Typescript 时出错

Question

I am trying to use useRef as shown below with typescript strict set to On, but I keep getting 'Object is possibly 'undefined'.

  const inputRef = React.useRef();
  const updateSelectionStart = () =>
    setSelectionStart(inputRef.current.selectionStart);

I also tried with this:

const inputRef = useRef<HTMLInputElement>(null);
and
const inputRef = useRef<HTMLInputElement | null>(null);

And nothing.

Any suggestions about how to do it without typescript errors?

Answer 1

Try using typescript optional chaining feature as below:

const inputRef = React.useRef();
  const updateSelectionStart = () =>
    setSelectionStart(inputRef.current?.selectionStart);

Answer 2

I fixed it by doing this:

const updateSelectionStart = () => {
    setCursorPosition(inputRef.current!.selectionStart || 0);
};