export const Main = () => {
    const [title, setTitle] = useState('');
    
    return (
        <ChildComponent
            title={title}
            onChange={e => setTitle(e.target.value)}
        />
    );
};

export const ChildComponent = ({ title, onChange }) => {
    return (
        <Box component="form" onSubmit={() => {}} noValidate mt={5}>
            <TextField
                fullWidth
                id="title"
                label="Title"
                name="title"
                autoComplete="title"
                autoFocus
                color="primary"
                variant="filled"
                InputLabelProps={{ shrink: true }}
                value={title}
                onChange={onChange}
            />
        </Box>
    );
};

const linearSearch = (arr, item) => {
  for (const i in arr) {
    if (arr[i] === item) return +i;
  }
  return -1;
};

linearSearch([2, 9, 9], 9); // 1
linearSearch([2, 9, 9], 7); // -1

new StringBuilder(hi).reverse().toString()

arr = [] // empty array
const isEmpty = arr => !Array.isArray(arr) || arr.length === 0;

// Examples
isEmpty([]); // true
isEmpty([1, 2, 3]); // false

const luhnCheck = num => {
  let arr = (num + '')
    .split('')
    .reverse()
    .map(x => parseInt(x));
  let lastDigit = arr.splice(0, 1)[0];
  let sum = arr.reduce(
    (acc, val, i) => (i % 2 !== 0 ? acc + val : acc + ((val *= 2) > 9 ? val - 9 : val)),
    0
  );
  sum += lastDigit;
  return sum % 10 === 0;
};

luhnCheck('4485275742308327'); // true
luhnCheck(6011329933655299); //  true
luhnCheck(123456789); // false

const euclideanDistance = (a, b) =>
  Math.hypot(...Object.keys(a).map(k => b[k] - a[k]));
  
euclideanDistance([1, 1], [2, 3]); // ~2.2361
euclideanDistance([1, 1, 1], [2, 3, 2]); // ~2.4495