json-as

     ██ ███████  ██████  ███    ██        █████  ███████
     ██ ██      ██    ██ ████   ██       ██   ██ ██
     ██ ███████ ██    ██ ██ ██  ██ █████ ███████ ███████
██   ██      ██ ██    ██ ██  ██ ██       ██   ██      ██
 █████  ███████  ██████  ██   ████       ██   ██ ███████
 
    AssemblyScript - v1.0.0-beta.1
  

📚 Contents

• About
• Installation
• Usage
• Examples
• Performance
• License
• Contact

📝 About

JSON is the de-facto serialization format of modern web applications, but its serialization and deserialization remain a significant performance bottleneck, especially at scale. Traditional parsing approaches are computationally expensive, adding unnecessary overhead to both clients and servers. This library is designed to mitigate this by leveraging SIMD acceleration and highly optimized transformations.

💾 Installation

npm install json-as@1.0.0-beta.1

Add the --transform to your asc command (e.g. in package.json)

--transform json-as/transform

Alternatively, add it to your asconfig.json

{
  // ...
  "options": {
    "transform": ["json-as/transform"]
  }
}

If you'd like to see the code that the transform generates, run with JSON_DEBUG=true

🪄 Usage

import { JSON } from "json-as";

@json
class Vec3 {
  x: f32 = 0.0;
  y: f32 = 0.0;
  z: f32 = 0.0;
}

@json
class Player {
  @alias("first name")
  firstName!: string;
  lastName!: string;
  lastActive!: i32[];
  // Drop in a code block, function, or expression that evaluates to a boolean
  @omitif((self: Player) => self.age < 18)
  age!: i32;
  @omitnull()
  pos!: Vec3 | null;
  isVerified!: boolean;
}

const player: Player = {
  firstName: "Jairus",
  lastName: "Tanaka",
  lastActive: [2, 13, 2025],
  age: 18,
  pos: {
    x: 3.4,
    y: 1.2,
    z: 8.3
  },
  isVerified: true
};

const serialized = JSON.stringify<Player>(player);
const deserialized = JSON.parse<Player>(serialized);

console.log("Serialized    " + serialized);
console.log("Deserialized  " + JSON.stringify(deserialized));

Examples

⚡ Performance

The json-as library has been optimized to achieve near-gigabyte-per-second JSON processing speeds through SIMD acceleration and highly efficient transformations. Below are some key performance benchmarks to give you an idea of how it performs.

Raw Performance

Simple

Test Case	Serialization (ops/s)	Deserialization (ops/s)	Serialization (MB/s)	Deserialization (MB/s)
Vector3 Object	32,642,320 ops/s	9,736,272 ops/s	1,240 MB/s	369 MB/s
Alphabet String	4,928,856 ops/s	7,567,360 ops/s	975 MB/s	1,498 MB/s
Small JSON Object	[Fill Value]	[Fill Value]	[Fill Value]	[Fill Value]
Medium JSON Object	[Fill Value]	[Fill Value]	[Fill Value]	[Fill Value]
Large JSON Object	[Fill Value]	[Fill Value]	[Fill Value]	[Fill Value]

SIMD

Test Case	Serialization (ops/s)	Deserialization (ops/s)	Serialization (MB/s)	Deserialization (MB/s)
Vector3 Object	32,642,320 ops/s	9,736,272 ops/s	1,240 MB/s	369 MB/s
Alphabet String	20,368,584 ops/s	28,467,424 ops/s	3,910 MB/s	5,636 MB/s
Small JSON Object	[Fill Value]	[Fill Value]	[Fill Value]	[Fill Value]
Medium JSON Object	[Fill Value]	[Fill Value]	[Fill Value]	[Fill Value]
Large JSON Object	[Fill Value]	[Fill Value]	[Fill Value]	[Fill Value]

JavaScript

Test Case	Serialization (ops/s)	Deserialization (ops/s)	Serialization (MB/s)	Deserialization (MB/s)
Vector3 Object	2,548,013 ops/s	1,942,440 ops/s	97 MB/s	73 MB/s
Alphabet String	3,221,556 ops/s	2,716,617 ops/s	624 MB/s	537 MB/s
Small JSON Object	[Fill Value]	[Fill Value]	[Fill Value]	[Fill Value]
Medium JSON Object	[Fill Value]	[Fill Value]	[Fill Value]	[Fill Value]
Large JSON Object	[Fill Value]	[Fill Value]	[Fill Value]	[Fill Value]

Real-World Usage

Scenario	JSON Size (kb)	Serialization Time (ops/s)	Deserialization Time (ops/s)	Throughput (GB/s)
Web API Response	[Fill Value]	[Fill Value]	[Fill Value]	[Fill Value]
Database Entry	[Fill Value]	[Fill Value]	[Fill Value]	[Fill Value]
File Parsing	[Fill Value]	[Fill Value]	[Fill Value]	[Fill Value]

📃 License

This project is distributed under an open source license. You can view the full license using the following link: License

📫 Contact

Please send all issues to GitHub Issues and to converse, please send me an email at [e-mail]

• Email: Send me inquiries, questions, or requests at [e-mail]
• GitHub: Visit the official GitHub repository Here
• Website: Visit my official website at jairus.dev
• Discord: Converse with me on My Discord or on the AssemblyScript Discord Server

Changelog

2025-02-22 - 1.0.0-beta.1

• perf: add benchmarks for both AssemblyScript and JavaScript
• docs: publish preliminary benchmark results
• tests: ensure nested serialization works and add to tests
• feat: finish arbitrary type implementation
• feat: introduce JSON.Obj to handle objects effectively
• feat: reimplement arbitrary array deserialization
• fix: remove brace check on array deserialization
• feat: introduce native support for JSON.Obj transformations
• feat: implement arbitrary object serialization
• fix: deserialization of booleans panics on false
• fix: bs.resize should be type-safe
• impl: add JSON.Obj type as prototype to handle arbitrary object structures
• chore: rename static objects (schemas) to structs and name arbitrary objects as obj
• tests: add proper tests for arbitrary types
• fix: empty method generation using outdated function signature
• docs: update readme to be more concise