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Array[position] returning NaN when it should be returning a string

The Problem: You are going to be given a word. Your job is to return the middle character of the word. If the word’s length is odd, return the middle character. If the word’s length is even, return the middle 2 characters.

My Solution

function isOdd(num) {
  return num % 2;
}

function getMiddle(str) {
  const middleDigit = (str.length + 1) / 2;
  if (isOdd(middleDigit) === 1) {
    return str[middleDigit];
  } else {
    return str[middleDigit - 0.5] + str[middleDigit + 0.5];
  }
}
console.log(getMiddle(`the`));

But i’m receiving a NaN output, rather than h , where has str[input] deviated from the my intention?

Thanks in advance!

Answer

Your execution was a little bit off!

  • I changed your isOdd function to return a boolean value, instead of a number.
  • After every calculation of the middle digit I subtracted 1 from the result, as we are working with indexes (and they start the count of the positions at 0, instead of 1).
  • For the second middle digit when the word length is even, you just have to do “str.length/2”, no need for adding or subtracting 1.

    function isOdd(num) {
      return num % 2 === 1;
    }
    
    function getMiddle(str) {
      if (isOdd(str.length)) {
        return str[((str.length + 1) / 2) - 1];
      } else {
        return str[(str.length / 2) - 1] + str[str.length / 2];
      }
    }
    console.log(getMiddle(`the`));
    console.log(getMiddle(`root`));