Why does my loop stop when the number is 0?

Question

function enigma(inputValue) {
  var i = 0;
  while (inputValue) {
    if (++i == 5) inputValue = 0;
  }
  return i;
}
var whatAmI = enigma(5);
console.log(whatAmI);

<div>Hit F12 and go to the console to view output.</div>

The output I get is 5.

Why does JavaScript stop the loop if inputValue equals 0? Is this because I did not specify that as the condition in the while loop?

while needs a value which is true, 0 is false, while 1 is an infinite loop — , Nov 01 '15 at 12:49
Possible duplicate of [Is true == 1 and false == 0 in JavaScript?](http://stackoverflow.com/questions/12236271/is-true-1-and-false-0-in-javascript) — Sebastian Simon, Nov 01 '15 at 14:47

score 0 · Answer 1 · answered Nov 03 '15 at 16:59

This explains the basics of a while loop. The condition within the while loop checks if it is truthy/falsy. When i is equal to 5, the input is 0, which causes the condition to be false.

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/while

If you want to see some other crazy Javascript, check out these truthy/falsy examples.

http://blog.falafel.com/the-truth-about-false-in-javascript/

score -1 · Answer 2 · answered Nov 01 '15 at 11:35

-1

0 is false. You can check here

answered Nov 01 '15 at 11:35

xangy

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Thank man, I never knew the value 0 is seen as a false in javascript. – Mocrosoft Nov 01 '15 at 11:53
1

logically 0 is always false and 1 is true – Nov 01 '15 at 12:51
@Mocrosoft you can read more about JavaScript booleans here: http://www.w3schools.com/js/js_booleans.asp – xangy Nov 01 '15 at 13:57
@DanielRuf Except in bash/when dealing with program exit codes. – Siguza Nov 03 '15 at 17:00
Right, but this does not use boolean values but integer or strings. – Nov 03 '15 at 17:11

Why does my loop stop when the number is 0?

2 Answers2