如何在没有`var`的情况下重写这段代码？

我有以下代码,以根据索引1处的数组元素的值返回不同的对象

const myArray = Array(1,2,3)
const myOtherArray = Array(1,3,4) 
const myThirdArray = Array(1,5,7)

// Creates object from array and prints it
let toObject = function(x){
  var myObject
  if (x[1] == 2){
     myObject = {first: x[0],
      second: x[1],
      third: x[2]
    }
  }
  else if (x[1] == 3){
     myObject = {first: x[0],
      second: x[1]-1,
      third: x[2]
    }
  }
  else {
     myObject = {first: x[0],
      second: x[1]+1,
      third: x[2]
    }
  }
  
  return myObject
}

console.log(toObject(myThirdArray))

return { first: x[0],
   second: (x[1]+1) - (x[1] == 2) - 2*(x[1] == 3),
   third: x[2]
};