readme.markdown 2.57 KB
Newer Older
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130
# json-stable-stringify

deterministic version of `JSON.stringify()` so you can get a consistent hash
from stringified results

You can also pass in a custom comparison function.

[![browser support](https://ci.testling.com/substack/json-stable-stringify.png)](https://ci.testling.com/substack/json-stable-stringify)

[![build status](https://secure.travis-ci.org/substack/json-stable-stringify.png)](http://travis-ci.org/substack/json-stable-stringify)

# example

``` js
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

``` js
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:

``` js
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:

``` js
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:

```js
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](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