Package Exports

json-as/transform/lib/index.js

This package does not declare an exports field, so the exports above have been automatically detected and optimized by JSPM instead. If any package subpath is missing, it is recommended to post an issue to the original package (json-as) to support the "exports" field. If that is not possible, create a JSPM override to customize the exports field for this package.

Readme

AS-JSON

JSON for AssemblyScript focused on performance, low-overhead, and ease-of-use.

Installation

npm install json-as

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"]
  }
}

Usage

import { JSON } from "json-as/assembly";

// @json or @serializable work here
@json
class Vec3 {
  x!: f32;
  y!: f32;
  z!: f32;
}

@json
class Player {
  firstName!: string;
  lastName!: string;
  lastActive!: i32[];
  age!: i32;
  pos!: Vec3 | null;
  isVerified!: boolean;
}

const player: Player = {
  firstName: "Emmet",
  lastName: "West",
  lastActive: [8, 27, 2022],
  age: 23,
  pos: {
    x: 3.4,
    y: 1.2,
    z: 8.3
  },
  isVerified: true
};

const stringified = JSON.stringify<Player>(player);

const parsed = JSON.parse<Player>(stringified);

Deviations from the spec

This implementation does not hold strongly to the JSON specification. Rather, design and behavior are inspired by the JSON implementation found in Google's v8 engine.

No support for dynamic types
Unsafe by design--parser assumes valid JSON
Partial whitespace support--parser prefers speed over handling whitespace effectively. Users may use the removeWhitespace function provided by json-as/src/util.ts
Is not based off of the official spec, but rather the behavior of the JSON C implementation found in google's v8 engine
Support for scientific notation on integers. Float support coming soon.

Implemented features

Fully supports:

Strings
Integers
Floats (Scientific notation not implemented)
Booleans
Arrays
Objects
Date
Null

Performance

Here are some benchmarks I took with tinybench (JavaScript) and astral (AssemblyScript). I took the benchmarks using the minimal runtime which doesn't call the Garbage Collector, so you may expect a 10% to 40% decrease from low to high throughput.

Tests are run on Ubuntu/WSL2 with a AMD Ryzen 9 CPU

JavaScript Results (TinyBench/NodeJS 19) ┌───────────────────────────┬─────────────┬────────────────────┬──────────┐ │ Task Name │ ops / sec │ Average Time(ns) │ Margin │ ├───────────────────────────┼─────────────┼────────────────────┼──────────┤ │ 'Stringify Object (Vec3)' │ '817,816' │ 1222.76 │ '±3.55%' │ │ 'Parse Object (Vec3)' │ '726,115' │ 1377.19 │ '±3.21%' │ │ 'Stringify Number Array' │ '1,104,036' │ 905.77 │ '±6.48%' │ │ 'Parse Number Array' │ '1,114,053' │ 897.62 │ '±2.58%' │ │ 'Stringify String' │ '1,565,716' │ 638.69 │ '±2.04%' │ │ 'Parse String' │ '69,568' │ 14374.22 │ '±2.55%' │ └───────────────────────────┴─────────────┴────────────────────┴──────────┘

AssemblyScript Results (Runtime Minimal) ┌───────────────────────────┬─────────────┬────────────────────┬──────────┐ │ Task Name │ ops / sec │ Average Time(ns) │ Diff │ ├───────────────────────────┼─────────────┼────────────────────┼──────────┤ │ 'Stringify Object (Vec3)' │ '2,091,000' │ 417.22 │ -805ns │ │ 'Parse Object (Vec3)' │ '1,780,000' │ 539.02 │ -838ns | │ 'Stringify Number Array' │ '1,920,000' │ 445.43 │ -460ns │ │ 'Parse Number Array' │ '1,660,000' │ 597.17 │ -300ns │ │ 'Stringify String' │ '1,280,000' │ 736.27 │ +97ns │ │ 'Parse String' │ '4,230,000' │ 239.21 │ -14135ns │ └───────────────────────────┴─────────────┴────────────────────┴──────────┘

Issues

Please submit an issue to https://github.com/JairusSW/as-json/issues if you find anything wrong with this library