tupleSON

Your hackable JSON serializer/deserializer

---

Customizable serialization & deserialization.
Serialize almost[^1] anything!

[^1]:
🌀 Circular references not your thing? We agree & we don't support it.
But hey, feel free to make a PR add opt-in support for that if you need it!

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- 💡 JSON-compatible output
- 📖 Human-readable output
- 🔧 Customizable behavior – tailor it to your exact needs
- 🌊 Serialize & stream things like Promises or async iterators

> [!IMPORTANT]
> _Though well-tested, this package might undergo big changes and does not follow semver whilst on 0.x.y-version, stay tuned!_

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``ts
/ eslint-disable @typescript-eslint/no-unused-vars, n/no-missing-import /

import {
// Create serializer / deserializer
createTson,
// Serialize bigint
tsonBigint,
// Serialize Date
tsonDate,
// Serialize Maps
tsonMap,
// throws when encountering Infinity or NaN
tsonNumberGuard,
// Serialize regular expression
tsonRegExp,
// Serialize Sets
tsonSet,
// serialize a Symbol
tsonSymbol,
// Serialize URLs
tsonURL,
// Serialize undefined
tsonUndefined,
// throws when encountering non-registered complex objects (like class instances)
tsonUnknownObjectGuard,
} from "tupleson";

const tson = createTson({
/**
* The nonce function every time we start serializing a new object
* Should return a unique value every time it's called
* @default ${crypto.randomUUID} if available, otherwise a random string generated by Math.random
*/
// nonce: () => "__tson",
types: [
// Pick which types you want to support
tsonSet,
],
});

const myObj = {
foo: "bar",
set: new Set([1, 2, 3]),
};

const str = tson.stringify(myObj, 2);
console.log(str);
// (👀 All non-JSON values are replaced with a tuple, hence the name)

// ->
// {
// "json": {
// "foo": "bar",
// "set": [
// "Set",
// [
// 1,
// 2,
// 3
// ],
// "__tson"
// ]
// },
// "nonce": "__tson"
// }

const obj = tson.parse(str);

// ✨ Retains type integrity
type Obj = typeof obj;
// ^?
// -> type Obj = { foo: string; set: Set; }
`

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- See example in ./examples/async
- Test it on StackBlitz

🧩 Extend with a custom serializer

> [!IMPORTANT]
> When defining custom serializers, the array order matters! If a value passes the test for more than one custom serializer, the first wins.

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> See test reference in ./src/extend/temporal.test.ts

`ts
/ eslint-disable @typescript-eslint/no-unused-vars, n/no-missing-import, n/no-unpublished-import /
import { Temporal } from "@js-temporal/polyfill";
import { TsonType, createTson } from "tupleson";

const plainDate: TsonType = {
deserialize: (v) => Temporal.PlainDate.from(v),
key: "PlainDate",
serialize: (v) => v.toJSON(),
test: (v) => v instanceof Temporal.PlainDate,
};

const instant: TsonType = {
deserialize: (v) => Temporal.Instant.from(v),
key: "Instant",
serialize: (v) => v.toJSON(),
test: (v) => v instanceof Temporal.Instant,
};

const tson = createTson({
types: [plainDate, instant],
});
`

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> See test reference in ./src/extend/decimal.test.ts

`ts
/ eslint-disable @typescript-eslint/no-unused-vars, n/no-missing-import, n/no-unpublished-import /
import { Decimal } from "decimal.js";

const decimalJs: TsonType = {
deserialize: (v) => new Decimal(v),
key: "Decimal",
serialize: (v) => v.toJSON(),
test: (v) => v instanceof Decimal,
};

const tson = createTson({
types: [decimalJs],
});
``

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> 💙 This package is based on @JoshuaKGoldberg's create-typescript-app.