Why is "0" is usually considered false but not with the ternary operator?

Asked Sep 04 '20 at 03:32

Active Sep 04 '20 at 03:32

Viewed 53 times

Evaluating the following statements in a browser's javascript console yields the results shown:

"0" == 0       // true
"0" == false   // true
"0" == true    // false
 0 ? true : false      // false
"0" ? true : false     // true   ???? WHAT  ???

The first four make sense but not the last one. Is this a bug? If not, how is the "0" being typecast in order to make it appear truthy, but why does this only happen for the ternary operator and not equality operator?

(Tested in multiple browser consoles with same result.)

asked Sep 04 '20 at 03:32

Ryan Griggs

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Never mind, I found this: https://stackoverflow.com/questions/30670964/why-does-using-0-with-the-ternary-operator-return-the-first-value – Ryan Griggs Sep 04 '20 at 03:32
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A non-empty string is never false-y – Pointy Sep 04 '20 at 03:33
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Use `===` and there are no surprises like this. `"0" === false` is false as is right and proper. – ggorlen Sep 04 '20 at 03:36
Yes, it's confusing, so use === to do the equal test – Keijack Sep 04 '20 at 03:38

Why is "0" is usually considered false but not with the ternary operator?

0 Answers0