@yingyeothon/codec

Tiny codec abstraction: a generic Codec<B> interface for encoding domain values into a base representation B (and decoding them back), plus a jsonCodec implementation that uses JSON strings.

Install

npm install @yingyeothon/codec

Usage

ESM:

import { jsonCodec, type Codec } from "@yingyeothon/codec";

interface Context {
  a: number;
  b: string;
}

const codec: Codec<string> = jsonCodec;
const encoded = codec.encode<Context>({ a: 10, b: "hello" });
const decoded = codec.decode<Context>(encoded);

CJS:

const { jsonCodec } = require("@yingyeothon/codec");

const encoded = jsonCodec.encode({ a: 10, b: "hello" });
const decoded = jsonCodec.decode(encoded);

Public API

• Codec<B> — interface with encode<T>(item: T): B and decode<T>(value: B): T.
• jsonCodec — stateless Codec<string> singleton backed by JSON.stringify/JSON.parse. Encoding undefined returns the literal string "undefined"; decoding undefined throws; decoding invalid JSON throws a SyntaxError.

Migrating from the legacy package

The legacy JsonCodec class is replaced by the stateless jsonCodec const: replace new JsonCodec() with jsonCodec. The Codec<B> interface is unchanged; packaging is dual ESM/CJS, Node >= 20.