Rocket.Chat/packages/apps-engine/deno-runtime/lib/codec.ts

import { Buffer } from 'node:buffer';
import { Decoder, Encoder, ExtensionCodec } from '@msgpack/msgpack';

import type { App as _App } from '@rocket.chat/apps-engine/definition/App.ts';
import { require } from './require.ts';

const { App } = require('@rocket.chat/apps-engine/definition/App.js') as {
	App: typeof _App;
};

const extensionCodec = new ExtensionCodec();

extensionCodec.register({
	type: 0,
	encode: (object: unknown) => {
		// We don't care about functions, but also don't want to throw an error
		if (typeof object === 'function' || object instanceof App) {
			return new Uint8Array(0);
		}

		return null;
	},
	decode: (_data: Uint8Array) => undefined,
});

// Since Deno doesn't have Buffer by default, we need to use Uint8Array
extensionCodec.register({
	type: 1,
	encode: (object: unknown) => {
		if (object instanceof Buffer) {
			return new Uint8Array(object.buffer, object.byteOffset, object.byteLength);
		}

		return null;
	},
	// msgpack will reuse the Uint8Array instance, so WE NEED to copy it instead of simply creating a view
	decode: (data: Uint8Array) => {
		return Buffer.from(data);
	},
});

export const encoder = new Encoder({ extensionCodec });
export const decoder = new Decoder({ extensionCodec });