json-bigint
This is a fork of json-bigint.
The difference is that it does not make any assumptions and always parse all numbers as BigNumber
s.
JSON.parse/stringify with bigints support. Based on Douglas Crockford JSON.js package and bignumber.js library.
Native Bigint
was added to JS recently, so we added an option to leverage it instead of bignumber.js
. However, the parsing with native BigInt
is kept an option for backward compability.
While most JSON parsers assume numeric values have same precision restrictions as IEEE 754 double, JSON specification does not say anything about number precision. Any floating point number in decimal (optionally scientific) notation is valid JSON value. It's a good idea to serialize values which might fall out of IEEE 754 integer precision as strings in your JSON api, but { "value" : 9223372036854775807}
, for example, is still a valid RFC4627 JSON string, and in most JS runtimes the result of JSON.parse
is this object: { value: 9223372036854776000 }
==========
example:
var JSONbig = require('json-bigint');
var json = '{ "value" : 9223372036854775807, "v2": 123 }';
console.log('Input:', json);
console.log('');
console.log('node.js built-in JSON:');
var r = JSON.parse(json);
console.log('JSON.parse(input).value : ', r.value.toString());
console.log('JSON.stringify(JSON.parse(input)):', JSON.stringify(r));
console.log('\n\nbig number JSON:');
var r1 = JSONbig.parse(json);
console.log('JSONbig.parse(input).value : ', r1.value.toString());
console.log('JSONbig.stringify(JSONbig.parse(input)):', JSONbig.stringify(r1));
Output:
Input: { "value" : 9223372036854775807, "v2": 123 }
node.js built-in JSON:
JSON.parse(input).value : 9223372036854776000
JSON.stringify(JSON.parse(input)): {"value":9223372036854776000,"v2":123}
big number JSON:
JSONbig.parse(input).value : 9223372036854775807
JSONbig.stringify(JSONbig.parse(input)): {"value":9223372036854775807,"v2":123}
Options
The behaviour of the parser is somewhat configurable through 'options'
options.strict, boolean, default false
Specifies the parsing should be "strict" towards reporting duplicate-keys in the parsed string.
The default follows what is allowed in standard json and resembles the behavior of JSON.parse, but overwrites any previous values with the last one assigned to the duplicate-key.
Setting options.strict = true will fail-fast on such duplicate-key occurances and thus warn you upfront of possible lost information.
example:
var JSONbig = require('json-bigint');
var JSONstrict = require('json-bigint')({ strict: true });
var dupkeys = '{ "dupkey": "value 1", "dupkey": "value 2"}';
console.log('\n\nDuplicate Key test with both lenient and strict JSON parsing');
console.log('Input:', dupkeys);
var works = JSONbig.parse(dupkeys);
console.log('JSON.parse(dupkeys).dupkey: %s', works.dupkey);
var fails = 'will stay like this';
try {
fails = JSONstrict.parse(dupkeys);
console.log('ERROR!! Should never get here');
} catch (e) {
console.log(
'Succesfully catched expected exception on duplicate keys: %j',
e
);
}
Output
Duplicate Key test with big number JSON
Input: { "dupkey": "value 1", "dupkey": "value 2"}
JSON.parse(dupkeys).dupkey: value 2
Succesfully catched expected exception on duplicate keys: {"name":"SyntaxError","message":"Duplicate key \"dupkey\"","at":33,"text":"{ \"dupkey\": \"value 1\", \"dupkey\": \"value 2\"}"}
options.protoAction, boolean, default: "error". Possible values: "error", "ignore", "preserve"
options.constructorAction, boolean, default: "error". Possible values: "error", "ignore", "preserve"
Controls how __proto__
and constructor
properties are treated. If set to "error" they are not allowed and
parse() call will throw an error. If set to "ignore" the prroperty and it;s value is skipped from parsing and object building.
If set to "preserve" the __proto__
property is set. One should be extra careful and make sure any other library consuming generated data
is not vulnerable to prototype poisoning attacks.
example:
var JSONbigAlways = require('json-bigint')({ protoAction: 'ignore' });
const user = JSONbig.parse('{ "__proto__": { "admin": true }, "id": 12345 }');
Links: