Javascript represents all numbers as double-precision floating-point. This means it loses precision when dealing with numbers at the very highest end of the 64 bit Java Long datatype -- anything after 17 digits. For example, the number:

714341252076979033

... bees:

714341252076979100

My database uses long IDs and some happen to be in the danger zone. I could change the offending values in the database, but that'd be difficult in my application. Instead, right now I rather laboriously ensure the server encodes Long IDs as Strings in all ajax responses.

However, I'd prefer to deal with this in the Javascript. My question: is there a best practice for coercing JSON parsing to treat a number as a string?

Javascript represents all numbers as double-precision floating-point. This means it loses precision when dealing with numbers at the very highest end of the 64 bit Java Long datatype -- anything after 17 digits. For example, the number:

714341252076979033

... bees:

714341252076979100

My database uses long IDs and some happen to be in the danger zone. I could change the offending values in the database, but that'd be difficult in my application. Instead, right now I rather laboriously ensure the server encodes Long IDs as Strings in all ajax responses.

However, I'd prefer to deal with this in the Javascript. My question: is there a best practice for coercing JSON parsing to treat a number as a string?

• javascript
• ajax
• largenumber

Share Improve this question Follow asked Apr 2, 2011 at 20:50 Dean MosesDean Moses 2,38222 gold badges2424 silver badges3636 bronze badges 1

• You'd have to write your own parser, probably. I doubt any stock JSON parser would have an option to do such a thing. – Pointy Commented Apr 2, 2011 at 20:54

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2 Answers 2

Sorted by: Reset to default 9

You do have to send your values as strings (i.e. enclosed in quotes) to ensure that Javascript will treat them as strings instead of numbers.

There's no way I know of to get around that.

JavaScript represents all numbers as 64b IEEE 754 floats.

If your integer can't fit in 52 bits then it will be truncated which is what happened here.

If you do need to change your database, change it to send 52 bit integers. Or 53 bit signed integers.

Otherwise, send them as strings.