simpleCalculator.js

/* You are required to create a simple calculator that returns the result of addition, subtraction, multiplication or division of two numbers.

Your function will accept three arguments:
The first and second argument should be numbers.
The third argument should represent a sign indicating the operation to perform on these two numbers.

if the variables are not numbers or the sign does not belong to the list above a message "unknown value" must be returned.

Example:
calculator(1,2,"+"); //=> result will be 3
calculator(1,2,"&"); //=> result will be "unknown value"
calculator(1,"k","*"); //=> result will be "unknown value"
Good luck! */

function calculator(a,b,sign){
    if(sign === '+' && Number.isInteger(a) && Number.isInteger(b)){
      return a + b 
    }if(sign == '-' && Number.isInteger(a) && Number.isInteger(b)){
      return a - b
  }if(sign == '*' && Number.isInteger(a) && Number.isInteger(b)){
      return a * b
    }if(sign == '/' && Number.isInteger(a) && Number.isInteger(b)){
      return a / b
      }else {
        return 'unknown value'
      }
    }