Built-in Types

json-as serializes and deserializes these out of the box — as fields of a @json class, or directly as the top-level type passed to JSON.parse<T> / JSON.stringify.

Category	Types
Numbers	i8–i64, u8–u64, f32, f64
Boolean	bool
Text	string
Time	Date
Collections	Array<T>, StaticArray<T>, Map<K, V>, Set<T>
Binary	typed arrays (Uint8Array, Float64Array, …), ArrayBuffer
Dynamic	JSON.Value, JSON.Obj, JSON.Raw

Primitives

Numbers and booleans map straight to JSON literals; strings are quoted and escaped.

import { JSON } from "json-as";

JSON.stringify<f64>(3.14); // '3.14'
JSON.stringify<i32[]>([1, -2, 300]); // '[1,-2,300]'
JSON.stringify(true); // 'true'
JSON.stringify('hi\n"x"'); // '"hi\\n\\"x\\""'

Date

Date serializes to an ISO 8601 string and parses back from one.

@json
class Event {
  name: string = "";
  at: Date = new Date(0);
}

const e = JSON.parse<Event>('{"name":"launch","at":"2024-05-26T07:02:05.000Z"}');
JSON.stringify(e); // '{"name":"launch","at":"2024-05-26T07:02:05.000Z"}'

Arrays

Array<T> and StaticArray<T> both serialize as JSON arrays.

JSON.parse<i32[]>("[1,2,3,4]"); // Array<i32>
JSON.stringify(JSON.parse<StaticArray<i32>>("[7,8,9]")); // '[7,8,9]'

Arrays nest freely — Vec3[][], string[], arrays of @json classes, and so on.

Map and Set

A Map serializes to a JSON object (keys must be strings); a Set serializes to a JSON array (duplicates collapse on parse).

const m = JSON.parse<Map<string, i32>>('{"a":1,"b":2}');
JSON.stringify(m); // '{"a":1,"b":2}'

const s = JSON.parse<Set<i32>>("[1,2,3,2]");
JSON.stringify(s); // '[1,2,3]'

Typed arrays and ArrayBuffer

Typed arrays serialize as JSON arrays of numbers and parse back element-for-element.

const bytes = JSON.parse<Uint8Array>("[10,20,30,40]");
JSON.stringify(bytes); // '[10,20,30,40]'

ArrayBuffer is supported through the same generic API:

const view = new Uint8Array(3);
view[0] = 1;
view[1] = 2;
view[2] = 3;

const encoded = JSON.stringify<ArrayBuffer>(view.buffer); // '[1,2,3]'
const decoded = JSON.parse<ArrayBuffer>(encoded);
decoded.byteLength; // 3

Dynamic values

When a field's type isn't known up front, use JSON.Value, JSON.Obj, or JSON.Raw. They can also hold built-in collections, typed arrays, and ArrayBuffer, and re-serialize them faithfully.