自己封装一个手机号334格式输入框

export default () => {
   const [value, setValue] = useState(null);
   const [start, setStart] = useState(0);
   const [key, setKey] = useState(null);

  useEffect(()=>{
    inputRef.current.selectionStart = start;
    inputRef.current.selectionEnd = start;
  }, [start, value])

  return (
      <input 
        ref={inputRef}
        value={value}
        onKeyDown={(e)=>{
          if(e.key === 'Backspace'){
            setKey('Backspace')
            setStart(e.target.selectionStart);
          }
        }}
        onChange={(e) =>{
          let value = e.target.value;
          let start = e.target.selectionStart;
          if(key === 'Backspace' && start === 3){
            value = value.replace(/[^\d]/g,'').replace(/\s*/g,"").slice(0, 11)
            value = `${value.slice(0,2)}${value.slice(3,4)} ${value.slice(4, 8)} ${value.slice(8, value.length)}`
            setValue(value);
            setStart(2)
            return
          }
          if(key === 'Backspace' && start === 8){
            value = value.replace(/[^\d]/g,'').replace(/\s*/g,"").slice(0, 11)
            value = `${value.slice(0,3)} ${value.slice(3, 6)}${value.slice(7, 8)} ${value.slice(8, value.length)}`
            setValue(value);
            setStart(7)
            return
          }
          value = value.replace(/[^\d]/g,'').replace(/\s*/g,"").slice(0, 11);
          if(value.length >= 7 && value.length < 12){
            value = `${value.slice(0, 3)} ${value.slice(3, 7)} ${value.slice(7, 11)}`;
          }
          if(value.length === 7){
            value = `${value.slice(0, 3)} ${value.slice(3, 7)} `;
          }
          if(value.length > 3 && value.length < 7){
            value = `${value.slice(0, 3)} ${value.slice(3, 7)}`;
          }
          if(value.length === 3){
            value = `${value.slice(0, 3)} `;
          }
          
          if(start < 3){
            setStart(start)
          }
          if(start === 3){
            setStart(start + 1)
          }
          if(start > 3 && start < 8){
            setStart(start)
          }
          if(start === 8 ){
            setStart(start + 1)
          }
          if( start > 8) {
            setStart(start)
          }
          if(start >= 13){
            setStart(13)
          }
          setValue(value)
          setKey(null)
        }} 
      />
  )
}