Измените массив в JavaScript, используя метод функции

//Given array
const ar=[1, 2, 3, 4, 5];
//Taking number from user to alter the array
var p=parseInt(prompt());
//Creating function body 
const addNumber=(arr, n)=>{  
    let arr1=[];
    for(let i=0;i<Math.max(arr.length);i++){
      arr1.push((arr[i]||0)+n)
    }
    return arr1;
  } 
//printing old array
  document.write("Old array: "+ar);
//printing new array by calling the function and passing the parametter
  document.write("new array: "+addNumber(ar, p)); 
  
Manaj Bera