How to append a string to another string after every N char?

Question

I am trying to create a program that adds "gav" after every second letter, when the string is written.

var string1  = "word"

Expected output:

wogavrdgav

Answer 1

You can use the modulus operator for this -

var string1  = "word";

function addGav(str){
  var newStr = '';
  var strArr = str.split('');

  strArr.forEach(function(letter, index){
    index % 2 == 1
      ? newStr += letter + 'gav'
      : newStr += letter
  })
  return newStr;
}

console.log(addGav(string1)); // gives wogavrdgav

console.log(addGav('gavgrif')) //gives gagavvggavrigavf....