Indexedcapitalization.js

// Given a string and an array of integers representing indices, capitalize all letters at the given indices.

// For example:

// capitalize("abcdef",[1,2,5]) = "aBCdeF"
// capitalize("abcdef",[1,2,5,100]) = "aBCdeF". There is no index 100.
// The input will be a lowercase string with no spaces and an array of digits.

function capitalize(s,arr){
  let arrStr = s.split('')
  for(let i = 0; i < arr.length; i++){
    //if the arr value is less than arr string length
    if(arr[i] < arrStr.length){
      //uppercase the value in the arrStr
      arrStr[arr[i]] = arrStr[arr[i]].toUpperCase() 
    }
  }
  //join the arrStr 
  return arrStr.join('')
};


function capitalize(s,arr){
  return [...s].map((x,i)=>arr.includes(i)?x.toUpperCase():x).join('')
};