Monday, November 02, 2009

The perils of Javascript - Number.MIN_VALUE

Just spent some time debugging a problem....

I had a filter set up in my new player code on runsat - and when the filter was disabled I was setting the filter limits to Number.MIN_VALUE and Number.MAX_VALUE.

When a calculation results in a number greater than Number.MAX_VALUE, it is assigned a value of Number.POSITIVE_INFINITY.

When a calculation results in a number less than Number.MIN_VALUE, it is assigned a value of Number.NEGATIVE_ INFINITY.


However.... this is complete "codswollop" - actually MIN_VALUE is an epsilon value - it's the smallest positive fraction allowed in javascript - so it's not negative - in fact it's almost (but not quite) zero.

Looking around loads of sites contain big info on this!

Yikes!

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