Seriall

Seriall is s simple serialization library for JavaScript / TypeScript, supports circular references and built-in types

Value	Serialized
12138	[12138]
true	[true]
16n	[{T:3,V:"16"}]
[80, 'http']	[[1,2],80,"http"]
Math	[{T:7,K:"Math"}]
new Set()	[{T:8,N:"Set",V:1},[]]
{ name: 'Steve' }	[{T:6,C:1,P:[["name",2,{}]]},{T:7,K:"Object"},"Steve"]

Features

• Supports built-in types (e.g., Map, Date, ArrayBuffer, Uint8Array)
• Supports circular references
• Serializable custom class instances
• Deep cloning capability
• Lightweight & dependency-free

Installation

deno	deno add jsr:@leawind/seriall
npm	npx jsr add @leawind/seriall
yarn	yarn dlx jsr add @leawind/seriall
pnpm	pnpm dlx jsr add @leawind/seriall
bun	bunx jsr add @leawind/seriall

Usage

Import seriall

import * as seriall from "@leawind/seriall";

Serialize

Stringify an object

seriall.stringify<T>(obj: T, options: SeriallOptions = {}): string;

Deserialize

Parse a string and get the object:

seriall.parse<T>(str: string, options: SeriallOptions = {}): T;

Deep clone

Deep clone an object. This function serialize the given object and then deserialize it.

seriall.deepClone<T>(obj: T, options: SeriallOptions = {}): T;

Examples

Simple value

const alice = { name: '' };
const json = seriall.stringify(alice);
const dolly = seriall.parse<typeof alice>(json);

assert(alice.name === dolly.name);

Instance of bulit-in Class

const original = {
	array: [2, 3, 4],
	set: new Set([12138, 7355608]),
	map: new Map(Object.entries({ greet: 'hello world' })),
	typed_array: new Int8Array([7, 6, 5, 4, 3]),
};

// deepClone means serialize and then deserialize
const cloned = seriall.deepClone(original);

assert(cloned.array.length === 3);
assert(cloned.set.has(12138));
assert(cloned.map.has('greet'));
assert(cloned.typed_array[2] === 5);

Instance of custom Class

class Cat {}
const mimi = new Cat();

// `mimi` is an instance of `Cat`, which is a custom Class.
// If you don't tell it how to get `Cat`, it won't be able to deserialize `mimi` and make it an instance of `Cat`. Therefore it refuses to serialize it.
assertThrows(() => seriall.purify(mimi), seriall.SeriallResolveFailedError);

// The second argument is telling seriall how to find class `Cat`: just by name "Cat"
const pure = seriall.purify(mimi, { palette: { Cat: Cat } });
console.debug(`mimi: `, pure);
// Output:  [ { T: 6, C: 1, P: [] }, { T: 7, K: "Cat" } ]

// It will be able to find constructor `Cat` and its prototype object by name "Cat" when deserializing.
const clonedMimi = seriall.parse(pure, { palette: { Cat } });
assert(clonedMimi instanceof Cat);

Builtin adapters

You may have noticed this in previous example about built-in class instance. Some types like Map, Date, Int8Array have their internal properties, they can't be simply described like regular object (for example: {name: 'Steve'}). So I have made some adapters for them.

These are supported builtin adapters.

• Number String Boolean
• Map Set
• Date RegExp URL URLSearchParams URLPattern
• ArrayBuffer DataView
• Uint8Array Uint8ClampedArray Int8Array Uint16Array Int16Array Uint32Array Int32Array Float16Array Float32Array Float64Array BigUint64Array BigInt64Array
• ImageData ByteLengthQueuingStrategy Headers

The implementation of those built-in adapters are at src/seriall/builtin/adapters.ts. You can also implement adapter for your custom Class.

Limitations

• Added properties on special instances
  Manually added properties to arrays or any class instances with adapters (e.g., Map, Date, ArrayBuffer) will be silently dropped.
  Example:

  const arr = [1, 2];
  arr.customProp = 'value'; // ❌ Won't survive serialization

• No field filtering
  All string-keyed own properties are serialized by default. Custom selection of serializable fields is not supported.

• Symbol-keyed properties
  Properties with Symbol keys will be ignored during serialization.

• JavaScript/TypeScript only
  Currently lacks cross-language support. Serialized data can only be deserialized in JavaScript/TypeScript environments.