NL-Marshal

Simple NodeJS utility to serialize or deserialize JS objects to Buffer or JSON.

Serializers

Boolean

Serialized buffer is 0x01 if serialized value is true and 0x00 otherwise.

import { bool } from "nl-marshal";
console.log(bool.toJSON(true)); // true
console.log(bool.fromJSON(false)); // false
const buffer = bool.toBuffer(true);
console.log(buffer); // 0x01
console.log(bool.toBuffer(false)); // 0x00
console.log(bool.fromBuffer(buffer)); // true

Empty

Serialized buffer is always empty. In JSON representation null will be used.

import { empty } from "nl-marshal";
console.log(empty.toJSON(undefined)); // null
console.log(empty.toJSON(null)); // null
console.log(empty.fromJSON(null)); // null
console.log(empty.toBuffer(undefined)); // <Buffer >
console.log(empty.toBuffer(null)); // <Buffer >
console.log(empty.fromBuffer(Buffer.from([]))); // null

Optional

Used to serialize optional values. Serialized buffer contains bool-byte at the start to show, value provided or not. In JSON representation returns null if no value provided.

import { optional, bool } from "nl-marshal";
const serializer = optional(bool);
console.log(serializer.toJSON(true)); // true
console.log(serializer.toJSON(undefined)); // null
console.log(serializer.toJSON(null)); // null
console.log(serializer.fromJSON(false)); // false
console.log(serializer.fromJSON(null)); // null
console.log(serializer.toBuffer(true)); // <Buffer 01 01>
console.log(serializer.toBuffer(undefined)); // <Buffer 00>
console.log(serializer.fromBuffer(Buffer.from('0100', 'hex'))); // false
console.log(serializer.fromBuffer(Buffer.from([0]))); // null

String

Serialized buffer contains length of string as varuint and utf-8 string.

import { string } from "nl-marshal";
console.log(string.toJSON('qwe')); // "qwe"
console.log(string.fromJSON('qwe')); // "qwe"
console.log(string.toBuffer('qwe')); // <Buffer 83 71 77 65>
console.log(string.fromBuffer(Buffer.from('83717765', 'hex'))); // "qwe"

Struct

import { struct, bool, string } from "nl-marshal";
const serializer = struct({ b: bool, s: string });
console.log(serializer.toJSON({ b: true, s: 'qwe' }));
// { b: true, s: "qwe" }
console.log(serializer.fromJSON({ s: 'qwe', b: true }));
// { b: true, s: "qwe" }
console.log(serializer.toBuffer({ s: 'qwe', b: true }));
// <Buffer 01 83 71 77 65>
console.log(serializer.fromBuffer(Buffer.from('0183717765', 'hex')));
// { b: true, s: "qwe" }

Varuint

Serializer for unsigned integers of unknown size. Serialized value can be string, number or BigNumber.

import { varuint, BigNumber } from "nl-marshal";
console.log(varuint.toJSON(123));
// 123
console.log(varuint.toJSON('123'));
// 123
console.log(varuint.toJSON(new BigNumber(123456789123456789)));
// "123456789123456789"
console.log(varuint.fromJSON('123'));
// <BigNumber 123>
console.log(varuint.toBuffer(123));
// <Buffer fb>
console.log(varuint.fromBuffer(Buffer.from('fb', 'hex')));
// <BigNumber 123>

UFixed

Serializer for unsigned fixed point numbers. Serialized value can be string, number or BigNumber. First argument is decimal places. The second one is boolean round, default is true.

import { ufixed, BigNumber } from "nl-marshal";
console.log(ufixed(4).toJSON(123.45678));
// 123.45678
console.log(ufixed(4).toJSON('123.45678'));
// 123.45678
console.log(ufixed(4).toJSON(new BigNumber('123456789123456789.987654321')));
// "123456789123456789.9877"
console.log(ufixed(4).fromJSON('123.456789'));
// <BigNumber 123.456789>
console.log(ufixed(4).toBuffer(123.456789));
// <Buffer 4b 2d 88>
console.log(ufixed(4).fromBuffer(Buffer.from('4b2d88', 'hex')));
// <BigNumber 123.4568>

Vector

Serializer for vector of static type. Serialized buffer starts with length of value as varuint

import { vector, varuint, BigNumber } from "nl-marshal";
const serializer = vector(varuint);
console.log(serializer.toJSON([123, '234', new BigNumber(345)]));
// ["123", "234", "345"]
console.log(serializer.fromJSON(['123', '234', '345']));
// [<BigNumber 123>, <BigNumber 234>, <BigNumber 345>]
console.log(serializer.toBuffer([123, '234', new BigNumber(345)]));
// <Buffer 83 fb 01 ea 02 d9>
console.log(serializer.fromBuffer(Buffer.from('83fb01ea02d9', 'hex')));
// [<BigNumber 123>, <BigNumber 234>, <BigNumber 345>]