Create function to convert from string to Integer using javascript

Create a function to convert a string to integer using JavaScript.

Javascript

function parseStringToInteger(inputValue: string): Number {
  let value: number;

  if (inputValue === '0' || Number(inputValue) === 0) {
    value = 0;
  } else if (inputValue === '') {
    value = null;
  } else {
    value = Number(inputValue);
  }

  return value;
}

How to use the above function to get the expected result : 

Javascript

const value = parseStringToInteger("25");
console.log(value);

Output : 25