162 lines
4.2 KiB
Markdown
162 lines
4.2 KiB
Markdown
# json-stable-stringify <sup>[![Version Badge][npm-version-svg]][package-url]</sup>
|
|
|
|
[![github actions][actions-image]][actions-url]
|
|
[![coverage][codecov-image]][codecov-url]
|
|
[![License][license-image]][license-url]
|
|
[![Downloads][downloads-image]][downloads-url]
|
|
|
|
[![npm badge][npm-badge-png]][package-url]
|
|
|
|
deterministic version of `JSON.stringify()` so you can get a consistent hash from stringified results
|
|
|
|
You can also pass in a custom comparison function.
|
|
|
|
[](https://ci.testling.com/ljharb/json-stable-stringify)
|
|
|
|
[](http://travis-ci.org/ljharb/json-stable-stringify)
|
|
|
|
# example
|
|
|
|
``` js
|
|
const stringify = require('json-stable-stringify');
|
|
|
|
const 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
|
|
|
|
``` js
|
|
const stringify = require('json-stable-stringify')
|
|
```
|
|
|
|
<a id="var-str--stringifyobj-opts"></a>
|
|
## const 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:
|
|
|
|
``` js
|
|
opts.cmp({ key: akey, value: avalue }, { key: bkey, value: bvalue }, { get(key): value })
|
|
```
|
|
|
|
For example, to sort on the object key names in reverse order you could write:
|
|
|
|
``` js
|
|
const stringify = require('json-stable-stringify');
|
|
|
|
const obj = { c: 8, b: [{ z: 6, y: 5, x: 4 },7], a: 3 };
|
|
|
|
const s = stringify(obj, function (a, b) {
|
|
return b.key.localeCompare(a.key);
|
|
});
|
|
|
|
console.log(s);
|
|
```
|
|
|
|
which results in the output string:
|
|
|
|
``` js
|
|
{"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:
|
|
|
|
``` js
|
|
const stringify = require('json-stable-stringify');
|
|
|
|
const obj = { d: 6, c: 5, b: [{ z: 3, y: 2, x: 1 }, 9], a: 10 };
|
|
|
|
const s = stringify(obj, function (a, b) {
|
|
return a.value < b.value ? 1 : -1;
|
|
});
|
|
|
|
console.log(s);
|
|
```
|
|
|
|
which outputs:
|
|
|
|
``` js
|
|
{"d":6,"c":5,"b":[{"z":3,"y":2,"x":1},9],"a":10}
|
|
```
|
|
|
|
An additional param `get(key)` returns the value of the key from the object being currently compared.
|
|
|
|
### 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:
|
|
|
|
```js
|
|
const obj = { b: 1, a: { foo: 'bar', and: [1, 2, 3] } };
|
|
|
|
const 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](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Using_native_JSON#The_replacer_parameter).
|
|
|
|
# install
|
|
|
|
With [npm](https://npmjs.org) do:
|
|
|
|
```
|
|
npm install json-stable-stringify
|
|
```
|
|
|
|
# license
|
|
|
|
MIT
|
|
|
|
[package-url]: https://npmjs.org/package/json-stable-stringify
|
|
[npm-version-svg]: https://versionbadg.es/ljharb/json-stable-stringify.svg
|
|
[deps-svg]: https://david-dm.org/ljharb/json-stable-stringify.svg
|
|
[deps-url]: https://david-dm.org/ljharb/json-stable-stringify
|
|
[dev-deps-svg]: https://david-dm.org/ljharb/json-stable-stringify/dev-status.svg
|
|
[dev-deps-url]: https://david-dm.org/ljharb/json-stable-stringify#info=devDependencies
|
|
[npm-badge-png]: https://nodei.co/npm/json-stable-stringify.png?downloads=true&stars=true
|
|
[license-image]: https://img.shields.io/npm/l/json-stable-stringify.svg
|
|
[license-url]: LICENSE
|
|
[downloads-image]: https://img.shields.io/npm/dm/json-stable-stringify.svg
|
|
[downloads-url]: https://npm-stat.com/charts.html?package=json-stable-stringify
|
|
[codecov-image]: https://codecov.io/gh/ljharb/json-stable-stringify/branch/main/graphs/badge.svg
|
|
[codecov-url]: https://app.codecov.io/gh/ljharb/json-stable-stringify/
|
|
[actions-image]: https://img.shields.io/endpoint?url=https://github-actions-badge-u3jn4tfpocch.runkit.sh/ljharb/json-stable-stringify
|
|
[actions-url]: https://github.com/ljharb/json-stable-stringify/actions
|