You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
178 lines
6.4 KiB
178 lines
6.4 KiB
# safe-stable-stringify
|
|
|
|
Safe, deterministic and fast serialization alternative to [JSON.stringify][].
|
|
Zero dependencies. ESM and CJS. 100% coverage.
|
|
|
|
Gracefully handles circular structures and bigint instead of throwing.
|
|
|
|
Optional custom circular values, deterministic behavior or strict JSON
|
|
compatibility check.
|
|
|
|
## stringify(value[, replacer[, space]])
|
|
|
|
The same as [JSON.stringify][].
|
|
|
|
* `value` {any}
|
|
* `replacer` {string[]|function|null}
|
|
* `space` {number|string}
|
|
* Returns: {string}
|
|
|
|
```js
|
|
const stringify = require('safe-stable-stringify')
|
|
|
|
const bigint = { a: 0, c: 2n, b: 1 }
|
|
|
|
stringify(bigint)
|
|
// '{"a":0,"b":1,"c":2}'
|
|
JSON.stringify(bigint)
|
|
// TypeError: Do not know how to serialize a BigInt
|
|
|
|
const circular = { b: 1, a: 0 }
|
|
circular.circular = circular
|
|
|
|
stringify(circular)
|
|
// '{"a":0,"b":1,"circular":"[Circular]"}'
|
|
JSON.stringify(circular)
|
|
// TypeError: Converting circular structure to JSON
|
|
|
|
stringify(circular, ['a', 'b'], 2)
|
|
// {
|
|
// "a": 0,
|
|
// "b": 1
|
|
// }
|
|
```
|
|
|
|
## stringify.configure(options)
|
|
|
|
* `bigint` {boolean} If `true`, bigint values are converted to a number. Otherwise
|
|
they are ignored. **Default:** `true`.
|
|
* `circularValue` {string|null|undefined|ErrorConstructor} Defines the value for
|
|
circular references. Set to `undefined`, circular properties are not
|
|
serialized (array entries are replaced with `null`). Set to `Error`, to throw
|
|
on circular references. **Default:** `'[Circular]'`.
|
|
* `deterministic` {boolean} If `true`, guarantee a deterministic key order
|
|
instead of relying on the insertion order. **Default:** `true`.
|
|
* `maximumBreadth` {number} Maximum number of entries to serialize per object
|
|
(at least one). The serialized output contains information about how many
|
|
entries have not been serialized. Ignored properties are counted as well
|
|
(e.g., properties with symbol values). Using the array replacer overrules this
|
|
option. **Default:** `Infinity`
|
|
* `maximumDepth` {number} Maximum number of object nesting levels (at least 1)
|
|
that will be serialized. Objects at the maximum level are serialized as
|
|
`'[Object]'` and arrays as `'[Array]'`. **Default:** `Infinity`
|
|
* `strict` {boolean} Instead of handling any JSON value gracefully, throw an
|
|
error in case it may not be represented as JSON (functions, NaN, ...).
|
|
Circular values and bigint values throw as well in case either option is not
|
|
explicitly defined. Sets and Maps are not detected! **Default:** `false`
|
|
* Returns: {function} A stringify function with the options applied.
|
|
|
|
```js
|
|
import { configure } from 'safe-stable-stringify'
|
|
|
|
const stringify = configure({
|
|
bigint: true,
|
|
circularValue: 'Magic circle!',
|
|
deterministic: false,
|
|
maximumDepth: 1,
|
|
maximumBreadth: 4
|
|
})
|
|
|
|
const circular = {
|
|
bigint: 999_999_999_999_999_999n,
|
|
typed: new Uint8Array(3),
|
|
deterministic: "I don't think so",
|
|
}
|
|
circular.circular = circular
|
|
circular.ignored = true
|
|
circular.alsoIgnored = 'Yes!'
|
|
|
|
const stringified = stringify(circular, null, 4)
|
|
|
|
console.log(stringified)
|
|
// {
|
|
// "bigint": 999999999999999999,
|
|
// "typed": "[Object]",
|
|
// "deterministic": "I don't think so",
|
|
// "circular": "Magic circle!",
|
|
// "...": "2 items not stringified"
|
|
// }
|
|
|
|
const throwOnCircular = configure({
|
|
circularValue: Error
|
|
})
|
|
|
|
throwOnCircular(circular);
|
|
// TypeError: Converting circular structure to JSON
|
|
```
|
|
|
|
## Differences to JSON.stringify
|
|
|
|
1. _Circular values_ are replaced with the string `[Circular]` (configurable).
|
|
1. _Object keys_ are sorted instead of using the insertion order (configurable).
|
|
1. _BigInt_ values are stringified as regular number instead of throwing a
|
|
TypeError (configurable).
|
|
1. _Boxed primitives_ (e.g., `Number(5)`) are not unboxed and are handled as
|
|
regular object.
|
|
|
|
Those are the only differences to `JSON.stringify()`. This is a side effect free
|
|
variant and [`toJSON`][], [`replacer`][] and the [`spacer`][] work the same as
|
|
with `JSON.stringify()`.
|
|
|
|
## Performance / Benchmarks
|
|
|
|
Currently this is by far the fastest known stable (deterministic) stringify
|
|
implementation. This is especially important for big objects and TypedArrays.
|
|
|
|
(Dell Precision 5540, i7-9850H CPU @ 2.60GHz, Node.js 16.11.1)
|
|
|
|
```md
|
|
simple: simple object x 3,463,894 ops/sec ±0.44% (98 runs sampled)
|
|
simple: circular x 1,236,007 ops/sec ±0.46% (99 runs sampled)
|
|
simple: deep x 18,942 ops/sec ±0.41% (93 runs sampled)
|
|
simple: deep circular x 18,690 ops/sec ±0.72% (96 runs sampled)
|
|
|
|
replacer: simple object x 2,664,940 ops/sec ±0.31% (98 runs sampled)
|
|
replacer: circular x 1,015,981 ops/sec ±0.09% (99 runs sampled)
|
|
replacer: deep x 17,328 ops/sec ±0.38% (97 runs sampled)
|
|
replacer: deep circular x 17,071 ops/sec ±0.21% (98 runs sampled)
|
|
|
|
array: simple object x 3,869,608 ops/sec ±0.22% (98 runs sampled)
|
|
array: circular x 3,853,943 ops/sec ±0.45% (96 runs sampled)
|
|
array: deep x 3,563,227 ops/sec ±0.20% (100 runs sampled)
|
|
array: deep circular x 3,286,475 ops/sec ±0.07% (100 runs sampled)
|
|
|
|
indentation: simple object x 2,183,162 ops/sec ±0.66% (97 runs sampled)
|
|
indentation: circular x 872,538 ops/sec ±0.57% (98 runs sampled)
|
|
indentation: deep x 16,795 ops/sec ±0.48% (93 runs sampled)
|
|
indentation: deep circular x 16,443 ops/sec ±0.40% (97 runs sampled)
|
|
```
|
|
|
|
Comparing `safe-stable-stringify` with known alternatives:
|
|
|
|
```md
|
|
fast-json-stable-stringify x 18,765 ops/sec ±0.71% (94 runs sampled)
|
|
json-stable-stringify x 13,870 ops/sec ±0.72% (94 runs sampled)
|
|
fast-stable-stringify x 21,343 ops/sec ±0.33% (95 runs sampled)
|
|
faster-stable-stringify x 17,707 ops/sec ±0.44% (97 runs sampled)
|
|
json-stringify-deterministic x 11,208 ops/sec ±0.57% (98 runs sampled)
|
|
fast-safe-stringify x 21,460 ops/sec ±0.75% (99 runs sampled)
|
|
this x 30,367 ops/sec ±0.39% (96 runs sampled)
|
|
|
|
The fastest is this
|
|
```
|
|
|
|
The `fast-safe-stringify` comparison uses the modules stable implementation.
|
|
|
|
## Acknowledgements
|
|
|
|
Sponsored by [MaibornWolff](https://www.maibornwolff.de/) and [nearForm](http://nearform.com)
|
|
|
|
## License
|
|
|
|
MIT
|
|
|
|
[`replacer`]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/JSON/stringify#The%20replacer%20parameter
|
|
[`spacer`]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/JSON/stringify#The%20space%20argument
|
|
[`toJSON`]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/JSON/stringify#toJSON()_behavior
|
|
[JSON.stringify]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/JSON/stringify
|