printing the result of the function to the console.

Question

var square = function(x){
   return x*x;
}
square(10);//100 

var square = function(x){
  var total = x*x;
  console.log(total);
}
square(10);//second way(probably wrong)

I was reviewing what I once wrote when passing the JS-track on codecademy.com. The task is incredibly simple - write a function that just squares a number and prints it in the console.
I did it the second way (using total variable inside the function block). Now I would do it the first way. Both seem to work. But is the second one really correct?

Well, in your second example the function doesn't return anything so it is pretty useless. Logging to the console is only used for debugging. I guess what you want in the first case is console.log(square(10)). — Felix Kling
– Felix Kling, Commented Jan 9, 2016 at 20:10
@Felix Kling, thank you very much. One more question. When I write console.log(square(10)) it returns 100 and then undefined. Why is that? — Don Draper
– Don Draper, Commented Jan 9, 2016 at 20:15
console.log prints the value to the console and doesn't return anything, hence the implicit return value of undefined. — Felix Kling
– Felix Kling, Commented Jan 9, 2016 at 20:22
Could you please accept one of the answers if it fulfills the question. — Johannes Jander
– Johannes Jander, Commented Jan 9, 2016 at 21:38

Johannes Jander · Accepted Answer · 2016-01-09 20:10:38Z

1

The second one is still correct if you want it printed to the console. In a real-world situation, you'd want the result returned to the calling function so it can do other things with the value and then it would fail, since your function does not return anything.

answered Jan 9, 2016 at 20:10

Johannes Jander

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Comments

clean_coding · Accepted Answer · 2016-01-09 20:10:24Z

1

Well the first one actually calculates the square root, so it's a usable function. The second one just prints it to the console - so I'd stick with the first one.

answered Jan 9, 2016 at 20:10

clean_coding

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Comments

jaiger · Accepted Answer · 2016-01-09 20:27:40Z

-1

Both methods work at correctly squaring the input, and there's nothing wrong syntactically in either function.

However, there is a problem with practicality. The first function only calculates the square of the input without giving out any return, or output, and therefore is not useful.

The second function is more practical because it logs the square of the input into the console, and therefore has an output, which in turn can be useful.

answered Jan 9, 2016 at 20:27

jaiger

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1 Comment

rghome Over a year ago

I think you have it the wrong way around. The first function does return something. The second one doesn't return anything.

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