Changing the value of your parameter is a code smell

Challenge Factorialize a Number has an issue. User Agent is: Mozilla/5.0 (Windows NT 6.3; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/51.0.2704.103 Safari/537.36. Please describe how to reproduce this issue, and include links to screenshots if possible.

I don’t believe we should encourage beginners to change the value of a parameter of a method. In the proposed code, the function factorialize returns “num”. It would be better form to create a var “result” to return it at the end - teaching good coding practices.

My code:

function factorialize(num) {
  var result = 1;
  for(var i=1;i<=num;i++) {
    result *= i;
  }
  return result;
}

factorialize(5);

[raisedadead]

I disagree that modifying input param is a bad practice, unless some one can point me to a concrete reference.

For instance, someone can rightly argue that each variable you declare is adding a new reference to the same object on the stack.

var actualVariable = 10;
var myVariable = actualVariable;
var yourVariable = myVariable;

All the above point to the location where 10 is stored, just with different references (variable names);

This is rather, waste of resources (not in this challenge), but when you do any memory intensive computing (visual renders, etc.)

Edit: Missed a point, that you could copy the data within a variable only when necessary, only when it is essential to work on a copy whilst preserving the original, else it is waste of assigning more variables than required.

IMHO modifying input param should be completely acceptable. JavaScript lets us do that and leveraging it should be the best practice not the other way round.

[Manish-Giri]

While I agree with @BerkeleyTrue’s point that the aim of the challenge is to help the camper to develop an algorithm and not necessarily talk about best practices in general, I don’t think it’s a good idea to modify method parameters. Here’s an interesting article that I found on this context.