119 lines
2.8 KiB
Markdown
119 lines
2.8 KiB
Markdown
# fast-json-stable-stringify
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Deterministic `JSON.stringify()` - a faster version of [@substack](https://github.com/substack)'s json-stable-strigify without [jsonify](https://github.com/substack/jsonify).
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You can also pass in a custom comparison function.
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[](https://travis-ci.org/epoberezkin/fast-json-stable-stringify)
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[](https://coveralls.io/github/epoberezkin/fast-json-stable-stringify?branch=master)
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# example
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``` js
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var stringify = require('fast-json-stable-stringify');
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var obj = { c: 8, b: [{z:6,y:5,x:4},7], a: 3 };
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console.log(stringify(obj));
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```
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output:
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```
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{"a":3,"b":[{"x":4,"y":5,"z":6},7],"c":8}
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```
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# methods
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``` js
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var stringify = require('fast-json-stable-stringify')
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```
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## var str = stringify(obj, opts)
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Return a deterministic stringified string `str` from the object `obj`.
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## options
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### cmp
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If `opts` is given, you can supply an `opts.cmp` to have a custom comparison
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function for object keys. Your function `opts.cmp` is called with these
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parameters:
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``` js
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opts.cmp({ key: akey, value: avalue }, { key: bkey, value: bvalue })
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```
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For example, to sort on the object key names in reverse order you could write:
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``` js
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var stringify = require('fast-json-stable-stringify');
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var obj = { c: 8, b: [{z:6,y:5,x:4},7], a: 3 };
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var s = stringify(obj, function (a, b) {
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return a.key < b.key ? 1 : -1;
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});
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console.log(s);
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```
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which results in the output string:
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```
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{"c":8,"b":[{"z":6,"y":5,"x":4},7],"a":3}
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```
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Or if you wanted to sort on the object values in reverse order, you could write:
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```
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var stringify = require('fast-json-stable-stringify');
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var obj = { d: 6, c: 5, b: [{z:3,y:2,x:1},9], a: 10 };
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var s = stringify(obj, function (a, b) {
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return a.value < b.value ? 1 : -1;
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});
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console.log(s);
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```
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which outputs:
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```
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{"d":6,"c":5,"b":[{"z":3,"y":2,"x":1},9],"a":10}
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```
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### cycles
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Pass `true` in `opts.cycles` to stringify circular property as `__cycle__` - the result will not be a valid JSON string in this case.
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TypeError will be thrown in case of circular object without this option.
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# install
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With [npm](https://npmjs.org) do:
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```
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npm install fast-json-stable-stringify
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```
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# benchmark
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To run benchmark (requires Node.js 6+):
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```
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node benchmark
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```
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Results:
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```
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fast-json-stable-stringify x 17,189 ops/sec ±1.43% (83 runs sampled)
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json-stable-stringify x 13,634 ops/sec ±1.39% (85 runs sampled)
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fast-stable-stringify x 20,212 ops/sec ±1.20% (84 runs sampled)
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faster-stable-stringify x 15,549 ops/sec ±1.12% (84 runs sampled)
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The fastest is fast-stable-stringify
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```
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# license
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[MIT](https://github.com/epoberezkin/fast-json-stable-stringify/blob/master/LICENSE)
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