These libraries are designed to provide stable and consistent stringification of JSON objects, ensuring that the output is predictable and can be compared reliably. They are particularly useful in scenarios where JSON data needs to be serialized in a consistent order, such as when generating hashes or signatures for data integrity checks. The main difference between the two packages lies in their handling of circular references and the dependency on the JSONify library.
json-stable-stringify
This is the same as https://github.com/substack/json-stable-stringify but it doesn't depend on libraries without licenses (jsonify).
deterministic version of JSON.stringify() so you can get a consistent hash
from stringified results
You can also pass in a custom comparison function.
example
var stringify = require('json-stable-stringify');
var obj = { c: 8, b: [{z:6,y:5,x:4},7], a: 3 };
console.log(stringify(obj));
output:
{"a":3,"b":[{"x":4,"y":5,"z":6},7],"c":8}
methods
var stringify = require('json-stable-stringify')
var str = stringify(obj, opts)
Return a deterministic stringified string str from the object obj.
options
cmp
If opts is given, you can supply an opts.cmp to have a custom comparison
function for object keys. Your function opts.cmp is called with these
parameters:
opts.cmp({ key: akey, value: avalue }, { key: bkey, value: bvalue })
For example, to sort on the object key names in reverse order you could write:
var stringify = require('json-stable-stringify');
var obj = { c: 8, b: [{z:6,y:5,x:4},7], a: 3 };
var s = stringify(obj, function (a, b) {
return a.key < b.key ? 1 : -1;
});
console.log(s);
which results in the output string:
{"c":8,"b":[{"z":6,"y":5,"x":4},7],"a":3}
Or if you wanted to sort on the object values in reverse order, you could write:
var stringify = require('json-stable-stringify');
var obj = { d: 6, c: 5, b: [{z:3,y:2,x:1},9], a: 10 };
var s = stringify(obj, function (a, b) {
return a.value < b.value ? 1 : -1;
});
console.log(s);
which outputs:
{"d":6,"c":5,"b":[{"z":3,"y":2,"x":1},9],"a":10}
space
If you specify opts.space, it will indent the output for pretty-printing.
Valid values are strings (e.g. {space: \t}) or a number of spaces
({space: 3}).
For example:
var obj = { b: 1, a: { foo: 'bar', and: [1, 2, 3] } };
var s = stringify(obj, { space: ' ' });
console.log(s);
which outputs:
{
"a": {
"and": [
1,
2,
3
],
"foo": "bar"
},
"b": 1
}
replacer
The replacer parameter is a function opts.replacer(key, value) that behaves
the same as the replacer
from the core JSON object.
install
With npm do:
npm install json-stable-stringify
license
MIT