jsonld-stable-stringify
v1.1.1
Published
deterministic JSON.stringify() with custom sorting to get deterministic hashes from stringified JSON-LD
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jsonld-stable-stringify
Deterministic version of JSON.stringify()
so you can get a consistent hash
from stringified JSON-LD. This is a clone of json-stable-stringify except
that arrays are sorted too (since JSON-LD arrays are interpreted as sets, so
order does not matter). The @list
keyword: arrays marked as lists are not sorted (and this applies recursively).
You can also pass in a custom comparison function.
examples
var stringify = require('jsonld-stable-stringify');
var obj = { c: 8, b: [{z:6,y:5,x:4},7], a: 3 };
console.log(stringify(obj));
output:
{"a":3,"b":[7,{"x":4,"y":5,"z":6}],"c":8}
var stringify = require('jsonld-stable-stringify');
var obj = {'@context':{a:{"@container": "@list"}}, a:[[3,2,1],[6,5,4]]};
console.log(stringify(obj));
output:
{"@context":{"a":{"@container":"@list"}},"a":[[3,2,1],[6,5,4]]}
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 jsonld-stable-stringify
license
MIT