Big number in JavaScript gets altered

Asked Oct 29 '13 at 11:29

Active Oct 29 '13 at 11:29

Viewed 110 times

I have a API that returns JSON object with field that was of type long on the server side. I noticed that the number gets malformed on client side. This is a sample:

var tmp = JSON.parse("9410110000000363");
console.log(tmp); // output: 9410110000000364

var tmp2 = 9410110000000363;
console.log(tmp2); // output: 9410110000000364

Any ideas why?

asked Oct 29 '13 at 11:29

dragonfly

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JavaScript numbers are only accurate up to around `4503599627370496`. See http://en.wikipedia.org/wiki/IEEE_floating_point - JS numbers (at least until we get value types in ES.next.next) are IEEE 754 floats. – Benjamin Gruenbaum Oct 29 '13 at 11:32
Interestingly, `9410110000000363+1` is also `9410110000000364`, and `9410110000000363-2` is `9410110000000362`. :) – James Donnelly Oct 29 '13 at 11:33
@JamesDonnelly Yes, of course it is, this is what the IEEE 754 specification means. I'm sure there is a duplicate somewhere. – Benjamin Gruenbaum Oct 29 '13 at 11:34
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Here [**read this**](http://www.2ality.com/2012/07/large-integers.html) this is an excellent source. – Benjamin Gruenbaum Oct 29 '13 at 11:35
You can try work with big numbers with this http://github.com/jtobey/javascript-bignum – RaphaelDDL Oct 29 '13 at 11:38

Big number in JavaScript gets altered

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