json-bignum

json-bignum

Node.js JSON replacement which handles 64-bit integers and arbitrary-precision decimals. It is a modified version of Douglas Crockford's JSON library. Although it can handle 64-bit integers and arbitrary-precision decimals, it is slower than the built-in JSON functions.

Install

$ npm install json-bignum

Usage

parse()

var bignumJSON = require('json-bignum');

var obj = bignumJSON.parse('{ "decimal": -9223372036854775807.4237482374983253298159 }');

stringify()

var bignumJSON = require('json-bignum');

var obj = {
    bigint: new bignumJSON.BigNumber('92233720368547758074237482374983253298159'),
    decimal: new bignumJSON.BigNumber('-9223372036854775807.4237482374983253298159'),
};

console.log(bignumJSON.stringify(obj));

BigNumber

The BigNumber class simply stores the number as a string. It does not support arithmetic, but if you need that here are some excellent libraries.

• BigDecimal.js: a literal port of Java's BigInteger and BigDecimal classes.
• bigint: Big integer arithmetic using GMP.
• bignum: Big integer arithmetic using OpenSSL.

// example using BigDecimal.js

var bignumJSON = require('json-bignum');
var bigdecimal = require('bigdecimal');

var jsonStr = '{"normal":-922337203.234,"big":-9223372036854775807.4237482374983253298159}';
var jsonObj = bignumJSON.parse(jsonStr);

var a = new bigdecimal.BigDecimal(jsonObj.normal.toString());
var b = new bigdecimal.BigDecimal(jsonObj.big.toString());
var sum = a.add(b);

jsonObj.sum = new bignumJSON.BigNumber(sum.toString());

console.log(bignumJSON.stringify(jsonObj));

Caveats

It is not recommended to mix calls to JSON and bignumJSON. For example, JSON.stringify() does not know how to parse BigNumber.

Benchmark

Below shows the result of the benchmark on my machine.

$ node benchmark.js
10000 calls of JSON.parse():                                   26.746847 ms
10000 calls of JSON.stringify():                               20.824071 ms
10000 calls of bignumJSON.parse() with bignums in JSON:        221.945307 ms
10000 calls of bignumJSON.parse() without bignums in JSON:     150.626292 ms
10000 calls of bignumJSON.stringify() with bignums in JSON:    64.166056 ms
10000 calls of bignumJSON.stringify() without bignums in JSON: 61.860016 ms