Well, today I'm not in good shape, and I expected the following code to

output just one zero. The code passes JSLint.



     /*jslint devel: true */



     (function () {

         'use strict';



         var isOneWayFlight = true, i;



         for (i = 0; i < isOneWayFlight ? 1 : 2; i += 1) {

             console.log(i);

         }

     }());



Instead, the runtime enters an infinite loop. It outputs: 0, 1, 2, ...



Correct version of the for statement, doing what I want:



     for (i = 0; i < (isOneWayFlight ? 1 : 2); i += 1) {

         console.log(i);

     }



That's just FYI.

It's a matter of priority.

First "<" will be executed, then "?".



So

i < isOneWayFlight ? 1 : 2

is the same as

(i < isOneWayFlight) ? 1 : 2



regarding to initial values:

true ? 1 : 2 => 1





And then your loop looks like this:

for (i = 0; 1; i += 1) {...}

That's why it's continues indefinitely









--

Keradus

On Tue, Feb 5, 2013 at 6:30 PM, Keradus <keradus@...> wrote:

> It's a matter of priority.



I know. Still the error slipped in, out of sloppiness, like many errors

that JSLint is designed to capture.

This is more of an error on the part of the knowledge of the developer

then on the part of JSLint. The code pattern is perfectly valid and not

confusing to someone who has a good grasp on operator precedence.

even if JSLint was to require () around the ternary operator and

results.

Such that your line

for (i = 0; i < isOneWayFlight ? 1 : 2; i += 1) {

would have thrown an error for missing () around ternary.You still could

have done

for (i = 0; (i < isOneWayFlight ? 1 : 2); i += 1) {

and the same error would have occurred in your logic.

See http://www.javascriptkit.com/jsref/precedence_operators.shtml for a

nice table on precedence of operators.





--- In jslint_com@yahoogroups.com, "Felix E. Klee"  wrote:

>

> On Tue, Feb 5, 2013 at 6:30 PM, Keradus  wrote:

> > It's a matter of priority.

>

> I know. Still the error slipped in, out of sloppiness, like many

errors

> that JSLint is designed to capture.

>







[Non-text portions of this message have been removed]

On Tue, Feb 5, 2013 at 11:17 PM, george_weilenmann <abyssoft@...>

wrote:

> This is more of an error on the part of the knowledge of the developer



Exactly not. I'm a C programmer for more than 20 years, and I'm well

versed with its operator precedence, which is similar to that of

JavaScript. I frequently use the `?` operator, and without any issues.



I just wanted to point out what happened to me today. That's all.

--- In jslint_com@yahoogroups.com, "Felix E. Klee"  wrote:

>     /*jslint devel: true */

>

>     (function () {

>         'use strict';

>

>         var isOneWayFlight = true, i;

>

>         for (i = 0; i < isOneWayFlight ? 1 : 2; i += 1) {

>             console.log(i);

>         }

>     }());

>

> Instead, the runtime enters an infinite loop. It outputs: 0, 1, 2, ...

>

> Correct version of the for statement, doing what I want:

>

>     for (i = 0; i < (isOneWayFlight ? 1 : 2); i += 1) {

>         console.log(i);

>     }





Thanks. Please try it now.

On Wed, Feb 6, 2013 at 3:47 AM, douglascrockford <douglas@...> wrote:

> Please try it now.



So quick - thanks! :-)

Nice compromise. Works great and indeed improves readability.



--- In jslint_com@yahoogroups.com, "Felix E. Klee"  wrote:

>

> Well, today I'm not in good shape, and I expected the following code to

> output just one zero. The code passes JSLint.

>

>     /*jslint devel: true */

>

>     (function () {

>         'use strict';

>

>         var isOneWayFlight = true, i;

>

>         for (i = 0; i < isOneWayFlight ? 1 : 2; i += 1) {

>             console.log(i);

>         }

>     }());

>

> Instead, the runtime enters an infinite loop. It outputs: 0, 1, 2, ...

>

> Correct version of the for statement, doing what I want:

>

>     for (i = 0; i < (isOneWayFlight ? 1 : 2); i += 1) {

>         console.log(i);

>     }

>

> That's just FYI.

>