Conversion and radices

Yesterday and this morning I had to convert data from one numeral system to another. first case : convert a number from decimal to binary!

For this, use toString(2). toString() is a method you use on a number and it returns a string. If you convert a radix, then the number will be converted to the corresponding numeral system. Example:

var num = 5;
var binary = num.toString(2);
console.log(binary); //'101'

Now let’s say you want to work the other way round. You’ve got a string, a radix, and you want to convert that string into decimal. In that case, you use parseInt(). Example with a function I wrote for an empireofcode challenge:

function convert(strNumber, radix) {
//this function will return -1 if the string cannot be converted into the indicated system.
 if (radix <= 10 && strNumber.match(/[a-z]/i)) {
    return -1;
}

var result = parseInt(strNumber, radix);

if (isNaN(result)) {
  return -1;
}

var check = result.toString(radix);

if (check === strNumber){
return result;
}
else{
 return -1;
 }
}