Port INN code validation from Java to JavaScript

Question

I want to validate the INN code. I have code snippet in Java which validates the INN code and want to port it to JavaScript to use it on my website (React):

for (int index = 0; index < lastCharacterIndex; index++) {
     sum += Character.digit(characters.get(index)) * INN_MULTIPLIERS[index];
}

checkDigit = (sum % 11) % 10;
returnValue = Character.digit(characters.get(lastCharacterIndex), 10) == checkDigit;
private static final int[] INN_MULTIPLIERS = {-1, 5, 7, 9, 4, 6, 10, 5, 7};

I tried to translate it but it fails:

const validateINNCode = (innCode) => {
    let sum = 0;
    const INN_MULTIPLIERS = [-1, 5, 7, 9, 4, 6, 10, 5, 7];
    for (let index = 0; index < innCode.length; index++) {
         sum += innCode[index] * INN_MULTIPLIERS[index];
    }
    const checkDigit = (sum % 11) % 10;
    const returnValue = innCode.length == checkDigit;
    return returnValue;
};

Any ideas how to correctly port this Java code to JavaScript? Thanks.

Answer 1

Porting code over from Java to JavaScript is a fairly easy task.

You should probably include the full Java code. Here is what I believe it would look like:

Note: I see that characters.get is called, so it looks like characters is a List<Character>. It would have been better to show how the Java code translated a String into this List.

import java.util.List;

public class Validator {
  private static final int[] INN_MULTIPLIERS = {-1, 5, 7, 9, 4, 6, 10, 5, 7};

  public static boolean isValid(List<Character> characters) {
    int sum = 0;
    int lastCharacterIndex = characters.size() - 1;
    for (int index = 0; index < lastCharacterIndex; index++) {
        sum += Character.digit(characters.get(index), 10) * INN_MULTIPLIERS[index];
    }
    int checkDigit = (sum % 11) % 10;
    return Character.digit(characters.get(lastCharacterIndex), 10) == checkDigit;
  }

  public static void main(String[] args) {
    // for (int i = 10000000; i < 99999999; i++) {
    //     String code = Integer.toString(i, 10);
    //     List<Character> digits = code.chars().mapToObj(e -> (char) e).toList();
    //     if (isValid(digits)) {
    //         System.out.println(i); // A valid code
    //     }
    // }

    String code = "18158984"; // Should be valid
    List<Character> digits = code.chars().mapToObj(e -> (char) e).toList();
    System.out.println(isValid(digits));
  }
}

Here is the equivalent JavaScript code:

1. The Character.digit can be ported over to parseInt
2. The == (double equals) in Java should be === (triple equals) in JavaScript

const INN_MULTIPLIERS = [-1, 5, 7, 9, 4, 6, 10, 5, 7];

function isValid(characters) {
  let sum = 0;
  const lastCharacterIndex = characters.length - 1;
  for (let index = 0; index < lastCharacterIndex; index++) {
    sum += parseInt(characters[index], 10) * INN_MULTIPLIERS[index];
  }
  const checkDigit = (sum % 11) % 10;
  return parseInt(characters[lastCharacterIndex], 10) === checkDigit;
}

const code = "18158984"; // Should be valid
const digits = code.split('');
console.log(isValid(digits));