Assuming a normal JavaScript engine, what could you possibly pass into the following mystery() function that would not thrown an error?

function mystery(a) {
  if (a === a) {
    throw new Error('The first argument has self equality.');

As is normal, this answer will be shown a week from when it was posted and will be linked to from here.The answer to this POW can now be found here.


ildar · March 19, 2013 at 9:05 AM

nan 🙂

ashwani · March 20, 2013 at 1:05 AM


POW Answer – JavaScript Self Inequality | Chris West's Blog · March 25, 2013 at 12:00 AM

[…] two people indicated in their comments in the original POW post, the answer is NaN. You can even do the following to check […]

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