Optimize my code

Question

I have written a simple calculator script and see duplicate code in it, how can I optimize it to be more DRY?
function Calculator() 
{
}
Calculator.divide = function(arg1, arg2) 
{
  return (arg1 / arg2);
}
Calculator.multiply = function(arg1, arg2) 
{
  return (arg1 * arg2);
}
Calculator.add = function(arg1, arg2) 
{
  return (arg1 + arg2);
}
Calculator.subtract = function(arg1, arg2) 
{
  return (arg1 - arg2);
}
do 
{
  var value1;
  var value2;
  var i = true;
  value1 = prompt('Enter 1st number');
  value2 = prompt('Enter 2nd number');
  var calcType = prompt('Enter a=add, s=subtract, d=divide, m=multiply, q=quit');
  if (calcType.toLowerCase() === "a") {
    var answer = Calculator.add( parseInt(value1), parseInt(value2) );
    alert('The answer is: ' + answer);
  } 
    else if (calcType.toLowerCase() === "s") {
    var answer = Calculator.subtract( parseInt(value1), parseInt(value2) );
    alert('The answer is: ' + answer);
  }
    else if (calcType.toLowerCase() === "d") {
    var answer = Calculator.divide( parseInt(value1), parseInt(value2) );
    alert('The answer is: ' + answer);
  }
    else if (calcType.toLowerCase() === "m") {
    var answer = Calculator.multiply( parseInt(value1), parseInt(value2) );
    alert('The answer is: ' + answer);  
  } 
    else if (calcType.toLowerCase() === "q") {
    break;   
    } 
    else {
      alert('You did not choose a correct arithmetic operator, try again.');
    }
} while (i)

Ezekiel dela Peña · Accepted Answer

Try
doing contructor with methods it will help you clean up your code a bit.
CHANGES stated at the bottom
```javascript
do {
value1 = parseInt(prompt("Enter 1st number: "));
value2 = parseInt(prompt("Enter 2nd number: "));
} while(isNaN(value1) === true 
     || isNaN(value2) === true);
function Calculator(num1, num2) {
  this.input1 = num1;
  this.input2 = num2;
  this.divide = function() {
    return this.input1/this.input2;
  }
  this.multiply = function() {
    return this.input1*this.input2;
  }
  this.addition = function() {
    return this.input1+this.input2;
  }
  this.subtraction = function() {
   return this.input1-this.input2;
  }
}
var calc = new Calculator(value1, value2);
var sum = calc.addition();
var product = calc.multiply();
var quotient = calc.divide();
var difference = calc.subtraction();
var calcBool = false;
while(calcBool != true) {
  var calcType = prompt("Enter a=add, s=subtract, d=divide, m=multiply, q=quit").toLowerCase();
  switch(calcType) {
    case 'a':
      alert("The answer is: " + sum);
      calcBool = true;
      break;
    case 's':
      alert("The answer is: " + difference);
      calcBool = true;
      break;
    case 'd':
      alert("The answer is: " + quotient);
      calcBool = true;
      break;
    case 'm':
      alert("The answer is: " + product);
      calcBool = true;
      break;
    case 'q':
      break;
    default:
      alert("You did not choose a correct arithmetic operator, try again.");
      break;
   }
}
```
For more efficient coding you can also use isNaN function search for it, it will help alot! ;)
Changes I've made: 
value2 = parseInt(prompt("Enter 2nd number: ")); enclosed the prompt with parseInt to avoid repitition of parseInt in latter part of the code.
used switch instead of if/else if to make the code more readable and to shorten the code.
did some contructor with methods to make the code look better(atleast for me, My Habit);
use isNaN in prompting value1 and value2 to ensure that the user will only input numbers.
prompt("Enter a=add, s=subtract, d=divide, m=multiply, q=quit").toLowerCase(); so that I won't repeat toLowerCase() in the switch case.
REFERENCE: https://www.codecademy.com/courses/spencer-sandbox/0/1?curriculum_id=506324b3a7dffd00020bf661

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Jacques vd Berg

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Optimize my code

Jacques vd Berg

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1 Answer

Ezekiel dela Peña

Ezekiel dela Peña

Jacques vd Berg

Jacques vd Berg