GitHub - japrescott/json-hardwire: json-hardwire is a very fast json.stringify replacement when you know the schema upfront

json-hardwire:

this is a fork of fast-json-stringify that is highly optimized for speed and unforgiving if your json doesnt match the schema. it is also json-schema incompatible as it adds new types for more optimizations

I made this for because fast-json-stringify is not very fast when it comes to long strings and horrible, when they are nested in array/object structures. If you know your data, you can let json-hardwire boost the creation of the stringified object.

see the benchmarks named hardwire to see the boost

Unforgiving types:

'hardString'
'hardInt'
'hardFloat'
'hardDate'
'hardJSONEncoded'

Benchmarks of json-hardwire:

Note: JSON.stringify is the baseline

Node 10.12.0:

Running benchmark "array"
=========================
JSON.stringify array x 3,481 ops/sec ±4.57% (84 runs sampled) 1x
json-hardwire array x 9,105 ops/sec ±0.32% (89 runs sampled) 2.7263565355565142x
json-fastify-json array x 6,514 ops/sec ±3.54% (87 runs sampled) 1.8897189013023814x
Fastest is json-hardwire array
slowest is JSON.stringify array is 63.321%slower

Running benchmark "arrayLongString"
===================================
JSON.stringify longString array x 1,086 ops/sec ±4.36% (85 runs sampled) 1x
json-hardwire longString array x 11,338 ops/sec ±0.53% (89 runs sampled) 10.835003078448604x
json-fastify-json longString array x 496 ops/sec ±1.35% (83 runs sampled) 0.4705407797725417x
Fastest is json-hardwire longString array
slowest is json-fastify-json longString array is 95.657%slower

Running benchmark "arrayComplex"
================================
JSON.stringify complex array x 272 ops/sec ±5.50% (78 runs sampled) 1x
json-hardwire complex array x 9,096 ops/sec ±0.37% (87 runs sampled) 35.15515986064193x
json-fastify-json complex array x 6,567 ops/sec ±2.70% (90 runs sampled) 24.805482688843536x
Fastest is json-hardwire complex array
slowest is JSON.stringify complex array is 97.155%slower

Running benchmark "stringLong"
==============================
JSON.stringify long string x 13,854 ops/sec ±5.24% (85 runs sampled) 1x
json-hardwire long string x 74,361,126 ops/sec ±0.48% (88 runs sampled) 5621.549221104614x
json-fastify-json long string x 13,640 ops/sec ±6.10% (81 runs sampled) 0.9765167621993757x
Fastest is json-hardwire long string
slowest is json-fastify-json long string,JSON.stringify long string is 99.983%slower

Running benchmark "stringShort"
===============================
JSON.stringify short string x 4,045,749 ops/sec ±0.66% (92 runs sampled) 1x
json-hardwire short string x 951,082,662 ops/sec ±0.41% (92 runs sampled) 235.6741284651254x
json-fastify-json short string x 29,783,720 ops/sec ±0.51% (91 runs sampled) 7.37315272778112x
json-fastify-json-uglified short string x 28,940,193 ops/sec ±2.63% (87 runs sampled) 7.016066571583278x
Fastest is json-hardwire short string
slowest is JSON.stringify short string is 99.576%slower

Running benchmark "object"
==========================
JSON.stringify obj x 1,624,338 ops/sec ±2.63% (87 runs sampled) 1x
json-hardwire obj x 11,181,532 ops/sec ±0.31% (86 runs sampled) 7.043029884363477x
json-fastify-json obj x 6,793,823 ops/sec ±0.48% (87 runs sampled) 4.272111048912816x
Fastest is json-hardwire obj
slowest is JSON.stringify obj is 85.802%slower

OLD DOCUMENTATION:

fast-json-stringify is significantly faster than JSON.stringify() for small payloads. Its performance advantage shrinks as your payload grows. It pairs well with flatstr, which triggers a V8 optimization that improves performance when eventually converting the string to a Buffer.

Benchmarks:

Node 6.11.2:

JSON.stringify array x 3,944 ops/sec ±1.13% (83 runs sampled)
fast-json-stringify array x 3,638 ops/sec ±2.56% (83 runs sampled)
fast-json-stringify-uglified array x 3,693 ops/sec ±1.75% (82 runs sampled)
JSON.stringify long string x 15,007 ops/sec ±1.13% (90 runs sampled)
fast-json-stringify long string x 14,480 ops/sec ±1.06% (87 runs sampled)
fast-json-stringify-uglified long string x 14,065 ops/sec ±1.22% (87 runs sampled)
JSON.stringify short string x 5,213,486 ops/sec ±1.35% (84 runs sampled)
fast-json-stringify short string x 12,314,153 ops/sec ±1.54% (83 runs sampled)
fast-json-stringify-uglified short string x 11,801,080 ops/sec ±6.65% (83 runs sampled)
JSON.stringify obj x 1,131,672 ops/sec ±16.67% (61 runs sampled)
fast-json-stringify obj x 3,500,095 ops/sec ±5.50% (80 runs sampled)
fast-json-stringify-uglified obj x 4,091,347 ops/sec ±1.33% (89 runs sampled)

Node 8.3.0:

JSON.stringify array x 4,025 ops/sec ±0.99% (90 runs sampled)
fast-json-stringify array x 6,463 ops/sec ±0.99% (90 runs sampled)
fast-json-stringify-uglified array x 6,314 ops/sec ±1.15% (92 runs sampled)
JSON.stringify long string x 14,648 ops/sec ±1.64% (88 runs sampled)
fast-json-stringify long string x 14,822 ops/sec ±1.09% (88 runs sampled)
fast-json-stringify-uglified long string x 14,963 ops/sec ±0.86% (89 runs sampled)
JSON.stringify short string x 4,724,477 ops/sec ±1.03% (89 runs sampled)
fast-json-stringify short string x 12,484,378 ops/sec ±0.92% (88 runs sampled)
fast-json-stringify-uglified short string x 12,218,181 ops/sec ±1.24% (90 runs sampled)
JSON.stringify obj x 1,898,648 ops/sec ±2.15% (85 runs sampled)
fast-json-stringify obj x 5,714,557 ops/sec ±1.45% (90 runs sampled)
fast-json-stringify-uglified obj x 5,902,021 ops/sec ±1.06% (91 runs sampled)

Example

const fastJson = require('fast-json-stringify')
const stringify = fastJson({
  title: 'Example Schema',
  type: 'object',
  properties: {
    firstName: {
      type: 'string'
    },
    lastName: {
      type: 'string'
    },
    age: {
      description: 'Age in years',
      type: 'integer'
    },
    reg: {
      type: 'string'
    }
  }
})

console.log(stringify({
  firstName: 'Matteo',
  lastName: 'Collina',
  age: 32,
  reg: /"([^"]|\\")*"/
}))

API

fastJsonStringify(schema)

Build a stringify() function based on jsonschema.

Supported types:

'string'
'integer'
'number'
'array'
'object'
'boolean'
'null'

And nested ones, too.

Additional Types for more ooomp:

'float'
'int'
'date'
'stringDirect' - use this when you dont have any chars in your string that need to be escaped like " \

Specific use cases

Instance	Serialized as
`Date`	`string` via `toISOString()`
`RegExp`	`string`

Required

You can set specific fields of an object as required in your schema by adding the field name inside the required array in your schema.
Example:

const schema = {
  title: 'Example Schema with required field',
  type: 'object',
  properties: {
    nickname: {
      type: 'string'
    },
    mail: {
      type: 'string'
    }
  },
  required: ['mail']
}

If the object to stringify is missing the required field(s), fast-json-stringify will throw an error.

Missing fields

If a field is present in the schema (and is not required) but it is not present in the object to stringify, fast-json-stringify will not write it in the final string.
Example:

const stringify = fastJson({
  title: 'Example Schema',
  type: 'object',
  properties: {
    nickname: {
      type: 'string'
    },
    mail: {
      type: 'string'
    }
  }
})

const obj = {
  mail: '[email protected]'
}

console.log(stringify(obj)) // '{"mail":"[email protected]"}'

Defaults

fast-json-stringify supports default jsonschema key in order to serialize a value if it is undefined or not present.

Example:

const stringify = fastJson({
  title: 'Example Schema',
  type: 'object',
  properties: {
    nickname: {
      type: 'string',
      default: 'the default string'
    }
  }
})

console.log(stringify({})) // '{"nickname":"the default string"}'
console.log(stringify({nickname: 'my-nickname'})) // '{"nickname":"my-nickname"}'

Pattern properties

fast-json-stringify supports pattern properties as defined by JSON schema.
patternProperties must be an object, where the key is a valid regex and the value is an object, declared in this way: { type: 'type' }.
patternProperties will work only for the properties that are not explicitly listed in the properties object.
Example:

const stringify = fastJson({
  title: 'Example Schema',
  type: 'object',
  properties: {
    nickname: {
      type: 'string'
    }
  },
  patternProperties: {
    'num': {
      type: 'number'
    },
    '.*foo$': {
      type: 'string'
    }
  }
})

const obj = {
  nickname: 'nick',
  matchfoo: 42,
  otherfoo: 'str'
  matchnum: 3
}

console.log(stringify(obj)) // '{"matchfoo":"42","otherfoo":"str","matchnum":3,"nickname":"nick"}'

Additional properties

fast-json-stringify supports additional properties as defined by JSON schema.
additionalProperties must be an object or a boolean, declared in this way: { type: 'type' }.
additionalProperties will work only for the properties that are not explicitly listed in the properties and patternProperties objects.

If additionalProperties is not present or is set to false, every property that is not explicitly listed in the properties and patternProperties objects,will be ignored, as described in Missing fields.
If additionalProperties is set to true, it will be used by JSON.stringify to stringify the additional properties. If you want to achieve maximum performance, we strongly encourage you to use a fixed schema where possible.
Example:

const stringify = fastJson({
  title: 'Example Schema',
  type: 'object',
  properties: {
    nickname: {
      type: 'string'
    }
  },
  patternProperties: {
    'num': {
      type: 'number'
    },
    '.*foo$': {
      type: 'string'
    }
  },
  additionalProperties: {
    type: 'string'
  }
})

const obj = {
  nickname: 'nick',
  matchfoo: 42,
  otherfoo: 'str'
  matchnum: 3,
  nomatchstr: 'valar morghulis',
  nomatchint: 313
}

console.log(stringify(obj)) // '{"matchfoo":"42","otherfoo":"str","matchnum":3,"nomatchstr":"valar morghulis",nomatchint:"313","nickname":"nick"}'

AnyOf

fast-json-stringify supports the anyOf keyword as defined by JSON schema. anyOf must be an array of valid JSON schemas. The different schemas will be tested in the specified order. The more schemas stringify has to try before finding a match, the slower it will be.

anyOf uses ajv as a JSON schema validator to find the schema that matches the data. This has an impact on performance—only use it as a last resort.

Example:

const stringify = fastJson({
  title: 'Example Schema',
  type: 'object',
  properties: {
    'undecidedType': {
      'anyOf': [{
	type: 'string'
      }, {
	type: 'boolean'
      }]
    }
  }
}

If/then/else

fast-json-stringify supports if/then/else jsonschema feature. See ajv documentation.

Example:

const stringify = fastJson({
  'type': 'object',
  'properties': {
  },
  'if': {
    'properties': {
      'kind': { 'type': 'string', 'enum': ['foobar'] }
    }
  },
  'then': {
    'properties': {
      'kind': { 'type': 'string', 'enum': ['foobar'] },
      'foo': { 'type': 'string' },
      'bar': { 'type': 'number' }
    }
  },
  'else': {
    'properties': {
      'kind': { 'type': 'string', 'enum': ['greeting'] },
      'hi': { 'type': 'string' },
      'hello': { 'type': 'number' }
    }
  }
})

console.log(stringify({
  kind: 'greeting',
  foo: 'FOO',
  bar: 42,
  hi: 'HI',
  hello: 45
})) // {"kind":"greeting","hi":"HI","hello":45}
console.log(stringify({
  kind: 'foobar',
  foo: 'FOO',
  bar: 42,
  hi: 'HI',
  hello: 45
})) // {"kind":"greeting","foo":"FOO","bar":42}

NB: don't declare the properties twice or you'll print them twice!

Reuse - $ref

If you want to reuse a definition of a value, you can use the property $ref.
The value of $ref must be a string in JSON Pointer format.
Example:

const schema = {
  title: 'Example Schema',
  definitions: {
    num: {
      type: 'object',
      properties: {
        int: {
          type: 'integer'
        }
      }
    },
    str: {
      type: 'string'
    }
  },
  type: 'object',
  properties: {
    nickname: {
      $ref: '#/definitions/str'
    }
  },
  patternProperties: {
    'num': {
      $ref: '#/definitions/num'
    }
  },
  additionalProperties: {
    $ref: '#/definitions/def'
  }
}

const stringify = fastJson(schema)

If you need to use an external definition, you can pass it as an option to fast-json-stringify.
Example:

const schema = {
  title: 'Example Schema',
  type: 'object',
  properties: {
    nickname: {
      $ref: 'strings#/definitions/str'
    }
  },
  patternProperties: {
    'num': {
      $ref: 'numbers#/definitions/num'
    }
  },
  additionalProperties: {
    $ref: 'strings#/definitions/def'
  }
}

const externalSchema = {
  numbers: {
    definitions: {
      num: {
        type: 'object',
        properties: {
          int: {
            type: 'integer'
          }
        }
      }
    }
  },
  strings: require('./string-def.json')
}

const stringify = fastJson(schema, { schema: externalSchema })

Long integers

Long integers (64-bit) are supported using the long module. Example:

const Long = require('long')

const stringify = fastJson({
  title: 'Example Schema',
  type: 'object',
  properties: {
    id: {
      type: 'integer'
    }
  }
})

const obj = {
  id: Long.fromString('18446744073709551615', true)
}

console.log(stringify(obj)) // '{"id":18446744073709551615}'

Uglify

If you want to squeeze a little bit more performance out of the serialization at the cost of readability in the generated code, you can pass uglify: true as an option. Note that you have to manually install uglify-es in order for this to work. Only version 3 is supported. Example:

Note that if you are using Node 8.3.0 or newer, there are no performance gains from using Uglify. See https://www.nearform.com/blog/node-js-is-getting-a-new-v8-with-turbofan/

const stringify = fastJson({
  title: 'Example Schema',
  type: 'object',
  properties: {
    id: {
      type: 'integer'
    }
  }
}, { uglify: true })

// stringify is now minified code
console.log(stringify({ some: 'object' })) // '{"some":"object"}'

Acknowledgements

This project was kindly sponsored by nearForm.

License

MIT

Name		Name	Last commit message	Last commit date
Latest commit History 18 Commits
bench		bench
test		test
.gitignore		.gitignore
LICENSE		LICENSE
README.md		README.md
bench.js		bench.js
example.js		example.js
index.js		index.js
package-lock.json		package-lock.json
package.json		package.json
server.js		server.js
string-concat.js		string-concat.js

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json-hardwire:

Benchmarks of json-hardwire:

OLD DOCUMENTATION:

Table of contents:

Example

API

fastJsonStringify(schema)

Specific use cases

Required

Missing fields

Defaults

Pattern properties

Additional properties

AnyOf

If/then/else

Reuse - $ref

Long integers

Uglify

Acknowledgements

License

About

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json-hardwire:

Benchmarks of json-hardwire:

OLD DOCUMENTATION:

Table of contents:

Example

API

fastJsonStringify(schema)

Specific use cases

Required

Missing fields

Defaults

Pattern properties

Additional properties

AnyOf

If/then/else

Reuse - $ref

Long integers

Uglify

Acknowledgements

License

About

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